Favorite: Ruger Bisley Single Six.
Least Favorite: Taurus M94.
The Bisley is about the most accurate handgun I own (many), or at least I am with it.
The Taurus has one of the roughest, heaviest, grittiest triggers I have ever encountered in a handgun. The rear sight loosens up after a cylinder full of ammo. It doesn't group to save its life. I tried to put lighter springs in it, but reducing weights caused light strikes, bad trigger reset, and timing issues. This is too bad, since my Taurus 669 (.357) is one of my favorite guns, being very accurate and having a marvelous trigger. (I bought the M94 because of my experience with the 669...)
-- Sam