I have a 16" heavy wilson barelled RRA LAR15 Carbine with mid length handguards & a fake telescoping stock. The thing is great! Reminds me of the Bushmaster 16" XM-15E2S I had.
I ordered mine from the factory, it took them about 4 weeks to send it. Which is not a bad thing, I'd rather them take their time building my rifle instead of pulling parts out of a barrel to assemble it!
They suprised me & put hogue grips on it. Pretty cool.
2 weekends ago I put at least 700-900 rds through it with no problems. I used a mixture of Remington & Wolf 55gr ammon.
The only criticism I've heard concerning Rock River is that it doesn't have a chrome lined barrel but instead has a Wilson Chrome Moly barrel.
I read recently that to chrome line a barrel they would have to over bore it then line it with chrome & give it rifling. The chrome moly barrel has chrome added to the make up of the steel of the barrel, causing chrome lining not to be needed.
I'm not sure if this is correct or not though.
Anywho, from my experience with this rifle I think you would be very happy with a Rock River.
Edit--> One thing I might sugest is to get a variant of the flat top receiver with detachable carry handle sights. I got the fixed carry handle A2 sights and occasionaly regret I can't mount optics as easily.