The G1 won't get very far considering it's locked down on T-Mobiles crappy 3G network (unless you happen to be on Wi-Fi or standing in an amazing good spot!) and since it doesn't want to play nicely with Exchange (probably it's biggest drawback).

Wait until the developers start moving with this and you will probably see a huge break-through in the market as far as open-source phones go.

...I'm still sticking to my CrackBerry