Hey!
I assumed that you are talking about C41 process B&W like Ilford XP and Kodak CN.
Personally I've use them since the real B&W film still better. But I've seen some people who use this type of film. They could be pretty good just don't expect this them to be the same as the real one.
As for the contrast. This also have to do with the lab you use. You should shoot a few rolls and drop off at different labs and see which one look best to you than stick with that lab.

Take care,
Buddy