A few comments on some of these posts....
If Y'all are worrying about debris, coins, keys, etc, getting lodged in the exposed hammer channel, DUH, DON'T PUT ANYTHING IN YOUR CARRY POCKET BUT DA GUN AND DA HOLSTER! C'mon, this is all common sense. (common sense, whazzat?)
As far as having some perp grab for your gun......they should never be that close to you that quickly. However, if they do, what's that left or right hand doing? Nothing? My pocket draw is almost always two-handed: the right draws the gun while the left holds the pocket holster and acts as a fending barrier while my gun comes into action.
For some of you semi-auto fans, many of those guns can be taken out of battery simply by pushing back the slider on the gun by as little as 1/8". So much for security.
I also prefer an exposed hammer, especially if you need to make a rare long-distance rescue shot in SA, and/or to clear a malfunction quicker. If you prefer the enclosed hammer, check out the 650 and 850 Taurus CIA. I don't know what they did to the triggers on these pieces but they are amazing.
Good luck in your search.