Firefox has been my main browser for years. If it's yours, I recommend avoiding this update unless you want a reason to go check out alternative browsers. This week I updated two macs, both PPC, to this version. One's running OS X 10.5.8, the other 10.4.11. On the 10.5.8 machine, after a few days and a few reboots I still get the "upgrade complete" screen when I start Firefox because every time I've opened it since the update, I've eventually had to use force quit to make it go away. On both machines the basic pattern is that Firefox just stops responding and the CPU goes to 100%. Often I've been in the middle of typing something, and suddenly I see the spinning beachball and the characters I was typing slow down to appearing at the rate of about one per minute.

So . . . until they get that fixed, if anyone knows of a good ad blocker that works for Safari 4 running under OS X 10.4, let me know.