Wearing one right now at the office.
Pros: Capable of concealing any handgun I own, and I'm a skinny bastard. The Storm is a bit large and gets uncomfortable all day; The P22, P32, or anything smaller (or, I'd wager, anything in between like a compact 1911) is just fine.
The shirt is built like a tank, everything double or triple stiched, and the workmanship for an off-the-shelf shirt is impressive.
The multitude of pen pockets is cool.
The "document pockets" are useful for not only your gun (see above) but I keep my PDA in the side opposite my gun.
Cons: The buttons, especially the topmost collar button, are extremely stiff and hard to work into or out of their holes.
The fabric is very heavy and inflexible, but softens up with washing. I imagine in the summertime it would be pretty hot.
Apparently the white ones have been discontinued...
Also, my black one seems to attract fuzz.