hi mike - MC5 and PT basically perform the same functions, but unfortunately your question is one that only you can answer, IMO. it's a matter of what's easier for your work flow.

I don't have PT to even compare the two myself. I have BIAB and RT, but my use is very different from yours. I use BIAB andRT to help me write new songs, then I use the real tracks for parts that I can't perform myself and I record everything in Sonar and import the MIDI or real tracks from RT/BIAB of the parts I can't perform ito sonar.

what do you use these programs for? for accompinament while you're playing live? for recording? those kinds of questions will help you determine which programs are best for your use.