Since Smith can only make good 44 specials and cant make a good 44 magnum, i would choose the 45 as my biased opinion. Rugers got them cornered in the 44. But they make one terribly awesome model 25 or 625.
I've prefered my 629's over any Ruger 44 I've owned. The old model Blackhawks were great guns, but the new models don't impress me as much.