There was just a massive (security) update to it in the last week.
The trouble with any version of IE is that it's incompatible with standards. Version 8 is better but still lags on bits and pieces that are 5 years old already. It's really only safe to use on Windows Update.
While I use Opera > 90% of the time, I don't see any problems with IE8. I've got it installed on almost all the computers I use. Got no compatibility or speed issues. It's definitely more stable than IE7 though.