have heard mixed reactions about them....
some people are happy with them, yet just as many people are not...
i'm not sure if PowerFC's have this feature or not, but 101 have a bad habit of locking tunes, and refuse to unlock them unless you pay $1000... so basically you either have to reset the computer and start from scratch, or keep going back to 101 for tunes... which, as i said, most people aren't happy with their level of tuning anyway....
refer to this thread for some more feedback on 101 (it's a bit of a long read, but worth it to see how unwilling they are to help out a customer, their general level of tuning, and their attitude)
http://www.performanceforums.com/forums/sh...p;highlight=101