My friend has one, but he's only getting started on app development using it. I'm wondering how locked down is it and is it as open as the hype says it is.
My understanding of Google's statements with regards to Android is that the initiative is meant to be "open" to carriers and manufacturers. The license is permissive and allows them to add in whatever they want and take away whatever they want. I remember someone from Google saying that they're allowed to completely strip away everything and lock it down completely if they wanted to.
Here is what I understand about the G1:
1. The Android OS is open source. That is, you can read the source, you can modify it and redistribute the modified source code.
2. The T-Mobile G1 requires the OS to be signed before updating it. That means if you modify the Android OS source yourself, you can't install it onto the device.
3. Applications are not allowed root. Getting root is considered an exploit.
4. Applications don't need to be signed by any authority to run on the phone.
Are these facts correct? If they are, the clear advantage over the iPhone seems to be #4, but as for #2 and #3... That's pretty much the same as it is for the iPhone. People seem to want to characterize Google's fixing of the Android jailbreak as security, while the very same people want to characterize Apple's fixing of iPhone jailbreaks as control freak-ness. Guys, it's pretty much the same thing. Google doesn't necessarily care about people modifying their platform, but T-Mobile does and Google is helping them achieve that.
As for #1, the advantage is pretty much entirely negated by the fact that it's Tivoization. After all, many components of the iPhone OS is also open source: XNU, WebKit. Most stuff except for the platform specific things that no one could possibly be interested in (sarcasm). Lots of the iPhone specific frameworks are also closed source, but for the most part, I don't really care about the details of how they manage to read PNG images. It may be interesting to read about the inner workings of SpringBoard (and the analogous Android UI), but if you can't modify those workings, then the knowledge becomes much less useful.
Android may be an open OS, but the T-Mobile G1 is not an entirely open platform. While the situation is much better, since while Google can blacklist apps, they don't have to whitelist them, so individuals are free to do most things on their phone... But in my opinion, it's disingenuous to call it an open platform. An open platform, in my opinion, is one you can modify, not just freely put stuff on.
It's a lot better situation than the Apple iPhone, certainly, but please people stop going up to me and going neener neener my platform is open while the one you choose to hack on isn't. Please. To do the stuff I'm doing with the iPhone on the T-Mobile G1, I'd have to use just as many exploits (or maybe not, since Android's security in that regard is apparently currently a bit swiss cheese, as can be expected on a new platform).