Screencasting - Post Production - FCP + Motion vs. Premiere Pro + AE

I am recording screencasts with camtasia 2 or screenflow and I am trying to select post-production software.

I have access to the entire CS6 suite with my subscription, but I also have a one-to-one setup for the next many months so I wouldn't have a problem working at the Apple store and having them teach me FCP and motion.

Can anyone shed some light on why I'd pick one set over the other?

Thanks.