I have one, and I like it very much. However, I've found that its not very comfortable with a 1911 unless you are wearing trousers that have a waistband about 2-3 inches bigger than what you normally wear. For my other guns, a Keltec P-11, and a Charter Arms .38 Undercover (about the same size a a S&W J frame, it works great. Just bear in mind that if you're sitting, such as in a car, etc., you won't be able to get to your weapon without practically standing up. I'm sort of glad the 1911 doesn't fit well, cause I would be hesitant to attempt to carry cocked and locked with the thunderwear holster due to the very close proximity of some very vital anatomy
Thunderwear is by far the best method of concealment for me that I have yet found.
With my Ultra CDP, I can be sitting, standing, crouching, bowling, golfing, or whatever, and I often forget it's there. I do not believe that I would be able to do it with any larger of a gun, but frankly, I wouldn't want to.
I highly recommend this holster. You might also want to consider a similiar product by www.smartcarry.com. My brother has the "white" version and he loves it. My next BTB holster will be one of those.