So whats the skinny with this gage? Who here uses one is it a worthwhile tool for the toolbox?

Gage

Is it a useful tool or a gimmick? They way i understand this tools usage is: you can measure a fired case from your rifle then set up your die to just bump the shoulder back a couple thousandths to prolong case life and improve consistency? Would that be correct?

yes that is correct. i use it with every rifle i own. i also bought the bullet comparator inserts to use with it. you don't need the whole kit because they fit in the insert for the head space set.
i just bought the bullet comparators for the calibers i needed. also works well with the hornady oal kit so you can get the distance to the lands. useing those 3 tools lets me get info like this

Nice!

Looks like itll be goin on the wishlist, Thank you

The Hornady headspace gauge is versatile and can be used on almost any cartridge and I also have one.

I also have ONE of the RCBS case gauges BUT at over $45.00 a pop for each cartridge guess which gauge is cheaper and just as accurate.

Below I use a GO gauge to give me a zero reference point, the Hornady gauge will give you the case length PLUS the length of the attachment on the calipers or a ball park reading of length.





Below no gauges, just trial and error until the case fits in the chamber and you decide how many thousandths smaller you want the cartridge case in relation to the chamber.

that shim kit looks awesome may have to get one.

IMO, it needs to be in the tool kit of every single reloader (I'm not exagerating for effect).  

A case gage is a poor substitute for one of these.  I have one and have several Precision Mics.  The Hornady/Stoney Point tool is both a superior tool and easier to use properly.

It's just a guess but I'd say about 50% of the troubleshooting posts on this forum could be avoided if the reloader had one of these and knew how to use it.  The percentage may be even higher but is unlikely to be dramatically lower.

So, count that as a resounding endorsement of a good piece of kit.

The Digital Headspace Gauge is also very helpful to handloaders.  

http://www.larrywillis.com/COAD-06.jpg

This tool is easy to use, and reading are VERY consistent.   It works on ALL different calibers and it doesn't need bushings, or expensive attachments.