LW betas have been really quite safe for me, but that's not the point.

Betas are betas BECAUSE they haven't been tested as much, so we SHOULD be careful.

Easy solution though: I just install betas on another admin account. If the beta wipes out the home directory, no problem: I only have files in that account that I know I might lose, and I don't worry about a beta messing the 'valuable' files I didn't get arouund to backing up

btw Lime-UK: what OS are you using? Someone here has probably tested the beta on a similar one.