I like how you can now use any SIP server for internet calling, but I haven't figured out how to get it to work with my Gizmo/SIPphone account either without using the native Gizmo app (I'd much prefer just a normal SIP client for it.)

Gmail's IMAP implementation is horrible from what I've seen, most clients have issues with it.

I just hope more programs are ported to OS2008 quickly, because there's been a bunch I couldn't use yet.