I've got a dozen STI 1911s and 2011s and my experience with their pistols has been outstanding. Granted I'm an STI junkie, but I got hooked because of the quality. Their pistols are built with tight tolerances in the fit (the frames are hand fitted to the slides), have silky smooth cycling, very nice crisp triggers, and are VERY accurate. STI originally made their reputation building high end competition pistols and you see a lot of them (or custom guns built on STI platforms) at IPSC/USPSA matches and that quality and attention to detail runs through all their pistols. It unfortunate that an earlier post mentioned a bad experience with STI customer service. I realize on occasion even the best companies slip, but my experiences with their customer service guys (there have only been a few) over the years have been nothing short of exceptional. They are very proud of the guns they build and stand behind them with a lifetime warranty that travels with the gun. Doesn't matter if you are the first owner or the tenth owner, the gun is under warranty. I also like the fact that they specialize in 1911s and their guns (with the exception of the entry level Spartan) are made from start to finish in Georgetown, TX.
I carry an STI as my EDC as does my son and my wife. I also shoot them competitively in IDPA and in local league matches. There are a lot of good 1911s out there (Colt, Springfield, etc.), but STI has never given me a reason to try anything else.
Check out the STI thread at the 1911Forum.
http://forums.1911forum.com/forumdisplay.php?f=44