Beta 3 will also be buggy. It's normal and I think this time we should wait till beta 5 or 6 to get a more stable OS. Even better, wait till the OS is final.
Of course if you have a development device to test it, then it's great. If you depend on your phone though, then I wouldn't suggest installing any beta. I have done it a lot of times and it wasn't nice...
I meant the bug also present in b1: if you
- use OTA for upgrade even from a clean, well-working b1
- restore a backup after a clean upgrade,
there will be some major battery drain.
There won't be a drain if you do a clean, non-OTA, no-backup-restored b2 install right from the IPSW file.