Back when I originally posted this, Google had sent a cease and desist letter to Cyanogen, one of the developers over at xda developers for using their google apps in his custom ROMS. It had appeared that Cyan wasn't going to develop any more of his custom roms for the G1 and that was one of the reasons I was jumping ship at the time. This has changed since then and he still develops for the G1, but I'm still switching to the N900.

Hope this helps.