What are your thoughts? Also, anybody have any idea the differences between the various MK17, MkG, MK4?

I bought a Banshee 9mm last year that I'm happy with it other than the brace removal shit show I bought into.  I have not shot the Dissent.
I know what you're saying about the designations.  I couldn't find anywhere they explained it and it took me a while to decipher.  
    It's all about the magazines they use.  
MK17 takes an M17 mag
MKG = a Glock mag various calibers
MK3 = 308 mag DPMS Gen 1 pattern
MK47 = AK47 mag
MK57 = FN 5.7 pistol mag
MK4 takes an M4 mag in 5.56 or 300 BO
MK4  in 9mm takes an M4 with their proprietary insert

It mostly makes sense once you figure out the code but it took me 20 minutes of WTF to piece it together.  

I do like that the new Dissent is FINALLY going with a FIXED EJECTOR!!
They should have done that day1 with the CMMG RDB Banshees.
However, the Dissent doesn't appear to be full auto capable without custom machining some kind of trip so they lost my interest.
I'm waiting on the MEAN Arms bearing delay

Thank you! That makes sense, just with CMMG would spell it out that simply. I have a Banshee and like it (well, technically it's my wife's...) but was curious about the Dissent for ease of a folding stock.

Do we have technical details regarding that?
Is this something which might be sold aftermarket?

When is the MEAN Arms product expected? Is it known to be select-fire capable?

What?  Are you referring to the fixed ejector in the CMMG Dissent?
If so, just look at their flashy ad when you hit AR15.com: https://cmmg.com/dissent?utm_source=ar15.com&utm_medium=banner&utm_campaign=ar15.com_homepage
Says right there it has a fixed ejector.  I personally haven't seen how they did it though.
Again, I presume you are referring to the fixed ejector?  I doubt it since it probably only works with their Dissent upper which is unlike a standard AR upper.
I also presume you've seen my million posts about all the ejector spring problems I had and then resorting to my own custom fixed ejector.  
If not, I have details on my site but I was forbidden to show pictures of mine.
https://c3junkie.com/?page_id=221

Link to MEAN Arms webpage to pre-order: https://www.meanarms.com/products/detail/reservation-for-bearing-delay-upper
It says right there, "Expected to begin shipping late Q1 - early Q2"
....and yes that is supposed to be 2023....so any day now, I would hope.

They showed it off at Shot and put info on their FB page however, I know a lot of people don't use FB.  I don't like to use it either.  So with their permission, I hosted info on my site and created a thread here:
https://www.ar15.com/forums/AR-15/MEAN-Arms-Bearing-delay-hopefully-really-happening-this-time-/15-778359/

A few weeks later, they created an industry account here and you can bug them direct here: https://www.ar15.com/forums/AR-15/MEAN-Arms-Bearing-delay-hopefully-really-happening-this-time-/15-778359/

However, it seems that while they went through the trouble to create an industry account (which costs money) they don't seem to be very responsive in answering questions.  I emailed them to let them know people are waiting for answers then they responded.

It is discussed on their FB page and several other threads that it is confirmed to be select fire capable.

You can see in the thread above that I mentioned that most videos on FB show it running pretty fast (which I don't like) but the video from range day at Shot Show looks like a nice RoF.
I uploaded it to my site: https://c3junkie.com/wp-content/uploads/2023/01/messages_0.mp4

No I meant the part about the Dissent needing some kind of custom machined sear trip to work in full auto.
Is that something anybody with a manual mill could produce?

I have. Thanks.
Was glad to see they went with a fixed ejector for this new model.

Glad to read it is select-fire capable.

I buy for my LE agency, and had reached out to CMMG in 2021 regarding their RDB products and they were not responsive either. I didn't ask MEAN Arms since theirs didn't seem anywhere close to a release. B&T sent us some demo weapons, and we ended up going with them. It was just 3 SMGs so small potatoes. B&T's SPC-9 wasn't out yet, and they had advised there were no plans to offer a select-fire model so we got the APC9-SD for our narcotics guys.

I can see it being challenging to reply to info requests when you're trying to get products out the door (especially a new product launch). Hopefully these will all do good things for the (not straight blowback) 9mm PCC/SMG market.

I have no idea.  I am just guessing since most of the carrier is chopped off.  Picture below is 556 as I can't find a picture of the 9mm but would presume it would use a similar carrier since it is RDB.
Even if one were to make a trip for it, I bet the cyclic rate would be very fast and not tunable so I'm not really interested in that either.
Which is why I am looking forward to the MEAN Arms RDB as it will use a standard buffer tube so you can tune with all the plethora of buffers and springs out there.

Don't you two remember the full-auto Olympic w/ the recoil spring up front?  They had to add a buffer tube stub for the longer carrier needed to trip the auto sear.  If CMMG added an auto sear trip to this, they'd have to add a stubby buffer tube for the end of the carrier.

The idea of a 16" 5.7x28mm Fold AR pistol w/ a fixed ejector that takes FN mags is intriguing - it's not $3k intriguing, however.  

Likely a trip like the Sig MCX uses would work.  As an 07/02, been contemplating one of these builds, but in 5.56 or .300 Blackout