I can't say if these two glitches are exist in common but at least it's on my two XP workstations.
I discovered the first glitch right after I installed the program. Two websites that I go quite often are www.nhl.com and www.nba.com. Both websites use the Flash a lot to get rich and very attractive visual effect, and their main menu like scores, stats, and standing are all embeded in the Flash. I don't have any problem before even in IE 7 Beta 1.0. However, in this new beta, I have to click twice to get into the page, the first click is to make the flash part in active, and the second is to active the link. I don't know why it would like this but kind annoying.
The second glitch is even more annoying. The back button in the top left corner sometimes doesn't really go back to the page that you just previously visit, it went to the previous website instead. This is very bad. For people like me who often use back button instead of the back link in the page would in danger to lost the data in the form in the current page. The best guess is that for those pages that don't go back properly usually contain the scripts or forms that refresh the current page to get updated data listed or something like that. This version of IE doesn't work well with this part.
The two glitches are still minor compare the overall achievement they made on this version. However, they would make it more close to perfect if they can fix them in the next release.