For the last year I haven't had problems on any system that I have run Linux on, and that includes a Intel iMac. This includes low end intel graphic chips, low end on board ATI chips, and high end nVidia setups. I haven't had a problem with youtube in a long time, I've watched entire movies on it before.
Like I said, I'm not saying I'm right and others are wrong, I just want a site that will crash firefox for me because of Flash problems. A lot of people can say it has problems but they can't put a link up for me to test.
It sounds like your problems are current zhasha, although I have no problems with youtube, but is everyone else just remembering what Flash was like a year or so ago? I agree Flash on Linux did suck, but the suck is gone. Also, you need to think in terms of what distro and what hardware are you using. Flash works fine on both low end and high end for me, on Sabayon and Ubuntu.
All I can judge by is my personal experiences, so for me Flash on Linux is great, 100%, and it looks like there are pretty good odds we'll see it on the Pandora.