Just got it installed and here are a couple things I encountered:
1) Upon first use it crashed my Vista Sidebar...going to reboot and see if that solves it.
2) I had a folder in my favorites list named "links" with a group of similar sites I browse and it somehow thinks this is the "favorites" folder which it is not, it is actually a subfolder in my favorites list. I noticed this issue with the beta version.
3) I have Vista 64bit and trying to open the IE 64 bit from your start menu causes an IE crash. I guess there is only one usable version of IE now where you could use the 64 bit version but not many pages supported it. Maybe IE 8 for Vista 64 is all inclusive in the one version?
That is all I found so far but IE8 seems really fast and full of new features to get used to.