Downloading it now...and it is v..e....r....y...s...l....o....w.
Meh. The price for early adoption or something like that.
edit- It looks like Thunderbird has also recently been updated to .9. Personally I'm looking forward to a 1.0 of Thunderbird as well as firefox. With the exception of my school have stupid servers and not letting me send outgoing mail, Thunderbird has been awesome.