Without question, I feel the KAC SR-15 E3 is worth every penny. Other than all it comes with out of the box, one of the best things about the SR-15 IMHO is how friggin' light it is when outfitted with the necessary accessories (in my case an aimpoint T-1, Surefire X300, MS2 sling and KAC handstop [now replaced with Larue FUG per my personal preference]).
The second best thing is how smooth the recoil (or lack thereof) is, especially when you add a muzzle brake to the carbine (doesn't need to be a Triple Tap brake by any means, a PWS FSC556 will certainly do the job, but I do love the TTB). I've yet to find any other carbine that recoils as smooth as the SR-15, nor one that I can fire as fast and completely maintain accuracy.
There's only 2 things I can think of that suck about the SR-15. The first is that since the barrel is so darn thin, if you're maintaining a very high rate of fire, especially in carbine classes, the rail gets so hot (even with the XTM rail covers I use) that it's hard to hold onto it with your bare support hand. In the summertime it's even worse. However, I personally consider that negative aspect to be completely voided by the fact that the gun is so damn lightweight. It's a give and take, and the extra heat is completely worth it IMHO. I just pull a Michael Jackson and wear a single glove on my support hand. People will give you shit about it until you outshoot the hell out of them... that tends to shut them up quickly
The other downside is the QD sockets in the lower. They're worthless. If you utilize them, they WILL cause the sling/sling swivel to get in the way of your thumb when activating the safety. And they unfortunately block the "ears" of the Magpul ASAP receiver end plate, causing you to have to cut the ears off in order to install one (thanks Titleist!). It's one of those things that sound great in theory, but fail in reality. If they could somehow magically be a little further back, they would kick serious ass. It's actually frustrating to me that they didn't work out for me, because I think the concept is really cool. Oh well.
Anyhoo, as with the heat issue, the rear QD issue (once again, IMHO) is voided out by the fact that it's SO lightweight and SO smooth to shoot.
Oh BTW, did I already mention it's light and smooth to shoot with hardly any recoil??
Here she is on the scale:
Compared to a 10.5" SBR I had at one time. Less than a 1 ounce difference, pretty crazy:
I will be wearing this shirt to my next Magpul carbine class. **** yeah: