"Installation was quick, performance is great, way better than the previous one," said someone identified as "Ely" on Neowin.net's message forum. Another tester there, "cheesegoduk," added his (or her) two cents. "It installed in under an hour which is great considering I'm not even using my fast hard disk to test it on."
If you are unable to participate in the beta currently but want to, Microsoft is going to make the beta public again once the official RC1 build is available. With Vista's release only months away, one must wonder if Microsoft will still be able to release it, considering the outstanding bug list.