[koz]

I've got the AAC Mini4 and SAS Eadrom MX. Both only add about 4" to length past the brake. Since AAC was sold to Freedom Group, I haven't bought any of their stuff but it's a neat little can. While not "hearing safe", it's plenty comfortable to shoot under cover (range roof, indoors, etc.) with no hearing pro. The SAS seems quieter that the AAC. It has a "thread over mount" so it is more like a direct thread than the AAC, Surefire, etc.. but you still have the brake if you're not shooting with a can. Also a little more repeatable.

The Surefire is a great can but I think you're paying some for the name. I've got their 556RC and 556RC-2 (they're 6.2") and on a 16" rifle, they don't feel long.

Another company is Griffin Armament - M4SD-K only adds 3.5" overall past the mount. They routinely meter very well.

The only reason I'd not do the Innovative Arms is the direct thread unless you're always going to have the can mounted. I know you'll never pull the can off during combat (it will burn the be-jesus out of you) but it is nice for transport to not worry about dinging threads or needing a thread protector. (I very much like direct thread cans for precision rifles but not AR's).

Another thing to consider is cost of mounts. If your AR is dedicated to that can, not a big deal, but let's say you have 3 AR's and you only want one can. The $130-150 per mount adds up. That's where the Griffin has an advantage is you can use A2 flash hiders on their M4SD cans.

Just so you can see some lengths (I know you're not interested in a .30 cal can but threw some in the pic just for reference).

SAS Reaper MX (.30)
SAS Eadrom MX
Griffin MDSDII (not the short version)
SF556RC-2
AAC Mini-4
SF762Mini (.30)
SF762SOCOM (.30) - It was used on some versions of the Mk13 rifle
Rugged Surge in short config (.30)

Hope this helps...