I installed Internet Explorer 7 Beta 3 yesterday. Beta 3 is the final beta release before the full release at the end of the year. Beta 3 was supposed to be a reliable version and as a final beta I would presume they were only expecting to uncover obscure bugs.
The IE 7 beta 3 makes some feature changes from the beta 2. The new version also provides reliability, compatibility and security fixes--more than 1,000 bugs have been dealt with in total, according to Microsoft.
Unfortunately it's not very reliable on my machine since it crashes within 10 seconds of starting up. I don't touch anything I just start it and 10 seconds later it crashes, even on www.microsoft.com as the picture shows.
Fortunately I switched to Firefox last year and have no problems running that. I've no religious type attachment to Firefox over IE7, I just switched because of all the security concerns with IE6 and I liked the tabbed browsing. If IE7 is better and safer than Firefox then I would probably switch back.
I only use IE for accessing Hotmail, and strangely that seems to work with IE7 though no other page does. Firefox can display the new Live hotmail anyway so that's not a problem. Uninstall doesn't seem to be an option as a work mate of mine did that last week and ended up with a machine that had no Internet explorer at all which he says "hosed" his machine. He did say that IE7 ran ok on his machine, before he uninstalled it.
The real worry is that Microsoft are going to push IE7 out as a "high priority" update to XP users at the end of the year. If IE7 is still crashing when they release it, even for a tiny percentage of users, and people have automatic updates on, then a lot of people are going to find themselves unable to access web sites one morning. Download your backup installer of Firefox now, just in case.