I have an 11.5 SR16, love it. Paid about 1425 I think for it, maybe 13 something I can't exactly recall.
The URX3.1 is probably one of the best rails ever made imo, and the URX4 on the SR15's is also excellent.
The SR16 has the MOD 1 gas system, as opposed to the newer MOD2 on the SR15s. Still...