Things I have done thus far to get the beta to work...
1)Downloaded and started installer. Noticed it'd get stuck in the setup bit. Did the following...
a)read beta forums extensively
b)changed internet explorer settings
c) deleted particular folders
d) finally had to open task manager, watch agent.exe like a hawk, kill it when its mem usage slipped backwards, then rerun it from the folder it resides in. Watched DOS window like hawk, looking for it to crash. Once it crashed, rerun. Keep going until you luck out and it manages to finish. I followed the instructions in this thread to finally get it to work.
2)Cheered as installer window finally popped up. Cursed when it crashed with an unexpected error at 11%. Wondered where the heck all my free drive space had gone. Freed up 20+ gigs (the installer needs at least 17) Repeated step d a couple more times, then called it a night. Left things running, woke up to 4 error reporting things, all telling me that agent had crashed. Really starting to hate agent.
3)Restarted in safe mode. Yup, that didn't help either.
4)Realized I've spent over 5 hours and I haven't even managed to get past 11% installation. Decided to say screw it for the moment, type this up, and post it.
And just to contrast with my Cataclysm beta experience, well, the only issue I had with that was the slow download speed.
So if you aren't in the beta yet, be happy. Seriously. If you're desperate for beta info, I'd go check this great blog I just found. Loads of beta analysis, mostly on stuff I like hearing about.