There's been so much backlash against the new version of FCP (FCPX) that Apple may have removed not just some but as of this post, all or nearly all reviews on the App Store (not to be confused with Amazon's Appstore, btw).
They're back up as of now.
9to5 has a post about it here.
Daring Fireball has more info about FCPX's reception in general here.
Arstechnica has some more reactions and comments from Apple on FCPX here.
Appleinsider has an article on reactions to FCPX here.