I discovered a nice and fairly extensive video: "G1 Android Walkthough" from Gizmodo. It demonstrates most if not all the features of the software and OS. The G1 has received generally positive, if mixed reviews from those who've used/seen it. And while people are mostly busy comparing the G1 to the iPhone, I think the more important discussion is how the G1 contributes to a growing smartphone market in the US and beyond.
For some context, here's AdMob data (August) on smartphone usage and traffic by handset/OS (from AdMob's network):
The charts are from AdMob:
The important point is about the momentum that all these phones, now including Android, help build collectively for the smartphone segment. Apple and now Google are raising the profile in the US and abroad of smartphones (certainly Nokia is doing that too as the global market leader).
Smartphone owners use the mobile Internet with greater frequency and intensity than feature phone users (here's the comScore data slide I've now shown many times):
Source: comScore/M:Metrics (Q1, 2008)
While feature phone users are driving huge SMS volumes in the US and abroad, the future of the "mobile Internet" is on smartphones, which is the growth sector of the market. By creating more competition and better user experiences, Apple and Google are helping grow the entire sector.
The G1/GPhone vs. the iPhone story misses this larger point.