The Android reviews also claimed it delivered. Consumers said otherwise.
The G1 is on T-Mobile, which is still a bit less than half as large in subscriber base compared to AT&T. The G1 also has sold well and I haven't met anyone who has one that doesn't love it.
I can flash random Android images onto mine, whether they be the most recent development branches of Android or customized ROMs for yet unreleased Android phones. The hacking community is really robust and is quick to provide speed, stability, and functionality updates, as well as detailed layman-friendly instructions for installation(though really it's all the same once you're used to it, update.zip in root of sdcard, Home+End while booting, Alt+L, Alt+S, Home+Back to reboot when it's done).
Once you're on 1.5+ you don't even need to wipe your data, like system settings, contacts, apps, etc. when you upgrade to a new build. It's totally painless, and even if it wasn't you're syncing to Google so you could bring back your PIM stuff over the air in a few minutes.
And all I've talked about is the software, don't forget the G1 has the best keyboard ever. A number row? Dedicated period key?(Blackberry doesn't have this!) Dedicated comma and @ keys? Customizable keyboard shortcuts for launching/switching between apps? Every symbol available, from Pound/Euro to pipe, tilde, backslash, brackets, and curly braces. Not to mention being perfectly sized and spaced, and having good tactile response. It's also a great slider mechanism, the weird arc thing is weird, but it means it's easy to open and close while nearly impossible to open or close on accident.
Like I said, I haven't heard a G1 owner say anything bad about it, and pretty much all the complaints levied by reviewers on release are solved in any decent 1.5+ ROM(auto-rotate, pdf reading, video playing/recording, multitouch). People love to say these new mobile platforms will get better with time, but so far Android is the only one that actually has. I hope the Pre(and iPhone) is as lucky in the end.