After using bazaar for a few weeks, I'm switching to mercurial because it is faster. I was seeing check across the network (using bzr+ssh) in of a modified quicken qdf file ( about 12mb) take 15 minutes or so. Using mercurial this takes just a few seconds. I imagine that mercurial is doing a better job of diffing binary files. Also mercurial has better error messages. Also, mercurial worked out of the box in cygwin - though I'm using the windows native mercurial now.
I still like some things about bazaar better. It seems to handle empty directories better - I'm not sure if mercurial handles them at all. Mercurial assigns a hex string to each version. Is it a hash key? Probably. These strings are more visible than I would like them to be.
I still may try git at some point. For now though, I'm using mercurial.