Adding to MKTJames comments, which I totally agree with. It all depends on what you really want to model. Equipping, say a Westside C-16 with proper motor, gearing and DCC equipment is probably going to run about the same as buying a Blackstone engine. So, if you're happy with C-19's and K-27's, Blackstone seems the way to go. If you want a C-16, or a T-12, go the brass route. For us eastern modelers, this is the only way we have to get the engines we want. Just don't do it with the expectation that you will recover every dollar put into its construction. Do it because you will end up with a unique model that will probably out perform the Blackstone stuff, and you built it.
brian b