I have the Colt Rail Gun, from what I understand it is essentially the same as MARSOC's M45 CQBP. It is hands down the best 1911 I have yet owned in terms of fit, finish, accuracy, and reliability. I have put ammo I've every flavor from steel case FMJ to ZMAX to Golden Saber, 185gr and 230gr.
I put 300+ rounds through it with plenty of lube and zero cleaning before I got a failure to feed. I swiped the feed ramp clean and continued shooting another 50 rounds with zero stoppages. She was down right disgusting on the inside when we got back from the range that day, I cleaned her up and she's still running like a tank. I firmly believe that as long as I clean her up every 100 rounds or so, jams will be few and VERY far between.
For comparison I have owned a Taurus 1911 and a Springfield Operator, the Taurus would only feed FMJ reliably and the Springer couldn't make it through 3 mags of anything without needing the feed ramp swiped clean (polishing the feed ramp probably would have solved it but I sold it). Neither one shot as accurately as my Colt has.
For 1911s that can be had for $900-1200 I don't believe there are many that can top it in any respect.
This is just my experience and opinions with it as an owner and up and coming 1911 nut, YMMV.
Cpl Williams, Evan T. USMC-R, 02-08-2010 ~
D Co, 4th CEB, Engineers UP!! OEF 21JUN-20SEP2011
REV. 19:11 And I saw heaven opened, and behold a white horse; and he that sat upon him was called Faithful and True, and in righteousness he doth judge and make war.