just like everything that first comes out.. you dont get it right away, you wait for them to workout the kinks and bugs. When its 100% stable ill get it.
2nd that. Im a IT professional and know almost everything about computers and I would have to say YES upgrade to firefox 3, But Firefox 2 is also great to have if you choose not to. If Firefox3 isnt working with your pc, then its probally your pc and not firefox thats buggin out. Ive tested hundreds of systems with Firefox3 and have not seen ANY issues yet.