I wouldn't trade my Taurus for a 642. I'd have to do 300 bucks worth of smithing on the 642 to get as good a trigger, frankly. I've not found another gun out of the box as good, but then, I've not tried the new Ruger LCR, either. I hear it's awesome. It's kinda fugly, but then, I don't buy guns for beauty pageants.
The 642 is affordable at under 500 bucks where I've seen 'em in Academys, though, and pretty much the standard in light weight pocket .38s. I consider getting one. It's plenty shootable out of the box as is. I'd get the pro, no lock.