Firefox vs Safari on Mac OS X

I confess I use Firefox, and I really prefer firefox user interface. But this is just stupid! I never had problems with Firefox before, and now that I have a fast machine and 8 GB of RAM Flash acts like this? OK, I know it is Flash.. but.. :-/

Also, no idea why I can’t get my Quicktime plugin to manage .mov files. It just does nothing. Check below how it behaves in Firefox and in Safari.