Couple of things I've found...
1, Won't launch Quicktime when I want to watch a Movie Trailer from Apple's Trailer site.
2, Complains about 'Potentially damaging content' on my iGoogle page and blocks it all!!.. it will let me 'Show All' but next time I got to my iGoogle page it complains again!!..
3, Crashes on a number of 'easy' sites: OcUK-Forums, CrackBerry, even Play.com
I'm testing it against Mozilla's Minefield (64bit) and it doesn't match up!!..
Only problem I have in Minefield is it uses twice the memory of FireFox!..