1. Yes, but the base membership is free and you can access the 3.1 beta
2. Not sure what you mean...I'm on a 5MB down connection and things are quite smooth with this version...better than 3.0.4. Rendering speed varies for client to client depending on their connection/hardware.
Gmail seems to much better now...they fixed the issue where the tab would always say 'loading...' and now it actually displays if there is a new email message.
The autocomplete on facebook no long lets me use the arrow keys to navigate to the item I want! Im sure it is the same way for other autocomplete that use the same JS framwork....