I have to weigh in, if only to just blab a bit.
I have owned a Colt Combat Commander, and after a $300 trip to the gunsmith it was a great gun. Fantastic. Before the smith it was a $700 paperweight with everything except FMJ, and even then only a couple of brands. Not a bad thing necessarily, just the facts. I loved that gun though.
My personal carry gun is a Glock 23. The only mod it has had is I installed a slightly extended mag release. It has, so far, been perfect with everything I've fired through it, as expected of any Glock. It's a gun that works out of the box.
The best example of astounding reliability has to go to my work gun, an HK USP Compact .40 with the LEM trigger. We were issued these out of the box. I and the rest of my class proceeded to put 1200 rounds through our guns in 4 and 1/2 days with NO CLEANING at all. Intentionally. This was not just range slow fire either, the guns were fired all over the place: off-handed bent elbow, upside down while the shooter was twisted around in a seat, rapid-fire etc... Out of the 15 guys I was with there was not one malfunction of any type. I was beyond impressed. I have access to this gun at a heavy discount and haven't purchased it, but the reason is only that I have a hard time concealing it and, frankly, I don't shoot it as well as the Glocks. Anyway, the point was I have to wonder if you could do the same with an out-of-the-box Colt (with duty ammo, not ball). Maybe you could.
Thanks for letting me ramble.