Our mmu never worked.  It was a bitch to get it to simply run.  My opinion is the mmu isn't debugged enough to be sold yet.  Good luck with it, you will need an enclosure to print stuff other than pla...

I ordered the kit for the same reason (lead time).

When Prusa says, "Our fastest customer built the kit in 4 hours!", take it with a grain of salt.  Picture the guy in the Domino's Pizza TV commercial folding boxes.

I highly recommend using the online instructions to compliment the printed instructions.  The online high-resolution pictures make it easier to identity the proper orientation of parts / assemblies.

I was happy with this purchase,

   Prusa i3 MK3 MK3s rubber foot 3030 frame upgrade kit

If you go this route, make sure to install the rubber feet before attaching the plates to the aluminum extrusions.  The instructions call for the stock feet to be installed after the plates are attached.

Good luck!  Obviously, you have a lot of experience with 3D printers.  I'm a total newbie.  I found the kit to be an extremely valuable learning experience.  I still need to print and assemble my Ikea Lack table enclosure.

My MK3 isn't working.  No power.  I need to get back into it and see what I wired wrong.

They are nice printers, I have ran the crap out of my mk3.

Only real complain about it is the hot end assembly. It is so packed in, you pretty much have to tare the whole thing apart to do any maintenance on it. Also may be the reason I just rebuild the whole hot end pretty much any time I have to tare it apart. From what I have heard they made it a bit easier to take apart on the mk3/s.

Last week a guy on reddit ordered a black one with the flex plate, got it in 5 days. The orange ones take longer he thinks.

tl;dr - I gush about my first 3d printer.

I sprung for the MK3s kit in August, delivered in September. It took me roughly 16 hours to assemble, but I took my time and viewed it as an opportunity to learn everything about my printer. This is my first printer and I don't know anybody with a printer IRL.

I have rarely been so impressed with a product; the packaging, the instructions, the parts quality, the support and the final finished printer. The instruction manual is clear and illustrated. Occasionally I had to resort to the online version of the assembly manual to zoom in on the high-resolution photos to double check what I was seeing in the manual. I used a sharpie with the manual to tick off each operation/step as it was completed and reviewed each page for completeness before moving on. That helped me avoid many mistakes during assembly.

I've had difficulty getting my Z offset dialed in, mostly because it's tough for me to see such small details with my aging eyes. I found it very instructive to print a single layer plate to get that worked out.  I've been printing mainly with PLA (Prusa's and Geeetech) and have not had any problems I can attribute to the filament.

I had some difficulty getting the first layer to stick while working on my Z offset; I experimented with the glue stick (thoughtfully included in the kit!) but ended up having the best results by cleaning the build plate with 99% isopropyl after each print and a once a week cleaning with acetone. I bought a bunch of each bulk on Amazon and some squeeze bottles to dispense. I rarely have a failure for the first layer to stick now.

I've been using TinkerCAD to design simple stuff and have just looked into Shapr3d which is expensive (not as expensive as others to be sure) and requires an iPad Pro and Apple Pencil. I've worked thru some of the Shapr3d tutorials and it's very nice to use after TinkerCAD. I would prefer to buy software like this "outright" rather than the SaaS models we now enjoy, but nobody asks me.

I've only ever used PrusaSlicer and so far it has been straight-forward to me. I don't know enough about other slicers to know how it compares (I understand PrusaSlicer is a fork of Cura).

Lastly, and you likely already know, Octoprint is the missing piece that enhances the usability of the printer. I have a Raspberry Pi 3B+ connected via USB-A to USB-B (supplied with the kit!) with a cheap Wyse v2 camera supplying a video stream. I keep my printer in the garage and it's nice to keep an eye on long prints (or cancel prints that have gone wrong, had a death whistle print go stringy towards the middle of the print when the filament got tangled on the roll, lessons learned).

I am very pleased with my MK3s and Prusa in general.

The only issue I had with my Mk3s kit was bed leveling using the factory spacers. When printing something that covered most of the print bed, you could see differences in the first layer over the entire printbed. Done the Nylon nut mod with a prusa octo print bed leveling addon and all is well. I thought the bed leveling sequence the printer does before each print would take care of that, but no.

Printed PLA, PETG, PC, and TPU so far. Nothing to complain about yet. Do have a click in the bed y axis, think its bearing related. After I had it for a week, I ordered build sheets and filament to justify the shipping. Need to order some spare parts just incase, again more filament.

Prusa slicer really takes the guess work out of alot of it. All my filament come from Prusa so far and the factory settings are spot on. Already printed all the factory parts and they look identical to what was sent in the kit. I manually changed speed using PLA to 150 or 180 mm/s (cant remember) and printed fine. Lost some fine detail, but function was good.

Thats a pretty good lead time, I might need to order one of these.

I found 2 mistakes:

The LCD ribbons were reversed.  Easy fix.  The self test lead me to the second problem.

The head sensor cable was not routed through the back plate with the cable bundle and won't allow the carriage full travel.  Now I have to pull it and hope I don't have to pull all of the plugs.

Lesson:  Go easy on the bourbon at midnight when assembling the printer.

Nice and congrats on your new printer!

I made the same mistake.  Every time they told me to eat a bear, I thought I as suppose to drink a beer.  Doh!

I love my Prusa i3 MK3S.  It's like 3D printing for dummies.

I'm always in need of a custom jig or part.  I recently put together a force gauge to measure Glock captive recoil spring assemblies,

I needed a jig to hold the recoil spring assembly.  I cranked out a jig using Fusion 360 in minutes,

NDZ Performance offers a tool to disassemble / assemble Glock gen4 - gen5 modular recoil spring assemblies.  I needed a modified version of the tool to work with a Glock 44 recoil spring assembly,

Again, minutes to design with Fusion 360.  Of course, a couple of hours to print (0.15 mm / 15% infill).

That's awesome.  I have 360, but I've only played in it a little.  I use AutoCAD daily, but only 2D doing site design.  I'm lost in 360.

I had absolutely zero CAD experience (2D or 3D) two months ago.  There's certainly a learning curve with Fusion 360 (I'm using the free version).  There are several multi-part Fusion 360 tutorials on Youtube.  I watched a tutorial or two, but then I just started hacking.  I now understand enough basic operations to design simple parts.  I export the design to an STL file.  Import the STL file into the PrusaSlicer.  Hit "Slice now" and save the resulting GCODE file to an SD card.  Done.

Prusament is made by them in house. It is really nice quality filament just a bit of a pain to get here in the US. Neat little gimmic is the QR code on the box will look up the info from the production of your spool and has a nice chart of the tolerancing sampling during the production.

I don't use the silent mode either.
About the only time you really notice the silent mode is on the rapids, it takes a lot of the high pitch noise out but if your in an area with ambient noise you don't really notice it at all.

I got mine fixed last night and ran the self test and everything is good.  Tonight I will load filament and do my first print (ever).

I really appreciate everyone, especially the OP, to take time to post tons of info on 3D printing.
I am totally out of my element.
Based solely on the advice here I ordered an assembled Mk3 a couple of weeks ago as well as a lot of atomic PLA & jumbo roll of clear PETG once I get comfortable with the printer.
Are there any spare parts, wear items, etc I should go ahead and order from Prusa as well?

Thank you.  I did order both plates.  I wasn't sure if/when I would need them but ordered both anyways since it did not cost much.
I ordered a sunlu dryer off amazon & will be storing all filament in a big gasketed box as suggested with dessicant.
I'll order a case of canned air now & typically keep the rest of the list of consumables on hand.

Also get one of these to hang above 3d printer

https://www.amazon.com/dp/B07D42CXWV?ref=ppx_pop_mob_ap_share

From exsperince I would also recomend the hotend upper and lower ptfe liner, and a heat break.

The ptfe liners will wear out over time.

The heatbreak is kindof a weak point in the E3d hot end design. They are only about one good crash away from bending/breaking. Also if the nozzle plugs up and the filiment back fills in to the heat break there is not a really good way to get it out. Often you are better off replaceing the heat break then trying to get the blockage removed.

Success!  I got everything calibrated and completed my first 3d print - the Prusa logo.  

Benchy is printing now.  Then, on to something useful.  What is useful?

I jumped on the bandwagon with the mmu v1. It was dogshit.
I then spent more money upgrading to the 2. It is slightly less smelly dogshit.
I'm back to just using one filament at a time.

I wish I could find a solid and reliable option for a two nozzle system for the prusa, then it would be perfect.

That was my original intention too, soluble supports. Multi color is cool too but the supports are what really interested me. I wasted $100 on wolf3d soluble supports only to have them decay before I could ever get using them properly.

I could just never get either mmu variant to be very reliable. I did manage to make a custom cataan game a while back. But it was painful how many failures I had.

This would be my preferred route now too, but you lose so much build volume but doing so... Or at least I can't figure out how to do it without that problem.

That's a pretty neat ideas actually after looking it up.
I'll be honest ever since I upgraded to the first gen mmu I miss the true direct drive setup -- bowdens are tough with TPU and I had to upgrade the tubes once due to friction points developing in them.  
The cool part is my filament stays protected from dust from storage to feeding to printing though.

That makes me smile.

I'm not sure of the "resolution" with which the G19.3 frame (above) was printed.  This print (below) appears to be more fine.

I also envision a "stipplator" with which you select your Glock frame (e.g., G17, G19, G26, G45, ...) and then you select from one of say, half a dozen popular stipple patterns.  The stipple would be printed into the frame.  The stipple should shift your focus away from the ringing.

Did you get the mmu2s yet? I dont remember what the lead time was?

I have seen a few videos on the palette? I think? It does 4 instead of 5 filaments, but havent seen much in the threads talking about it, anyone try it? Its pricey, but all ive heard is bad stuff about the mmu2s...

+1

I'd prefer a Prusa dual extruder, but if your MMU proves to be a no-drainer / foolproof / WSSD (Water-Soluble Supports for Dummies), I'm in!  I have no interest in multi-color.  I just don't want to be plagued by the horror story which is the Prusa MMU.