Shooting Budd has a .357/9MM Blackhawk 'Convertable', and he likes it very well, particularly when he wants to shoot cheap...installs the 9MM cylinder and blazes away. According to him, his accuracy is about the same, with the .357 having a very slight edge. I'm not a good enough shooter to tell.
When I want to 'shoot for cheap', I take my Single-Six with the .22LR cylinder