I would wait for it to become a stable script. Then I would try to see if I can upgrade my heavily modded forums. if not i will go on using the previous script.
I generally do not like using any script while it's still in beta, but I'm thinking about making an exception here.
1. I'd like to start up a new forum soon ..., hopefully by the end of the month.
2. I'd like to use phpBB again.
3. If I use phpBB, then I know that I'll need to upgrade to 3.0 very soon. Using 2.0.x at this point is kind of counter-productive in the long term.