As Android has grown, devices fall into one of two major classifications. Some devices are so-called "Google Experience" devices (featuring the phrase "with Google" somewhere on the device). Other devices are, well, not Google Experience devices. What is the difference? I've had a hard time figuring it out.
I think that Google Experience phones are updated by Google itself, while the rest of the devices are supported by the phone's manufacturer. I have an original G1 (a Google Experience phone), and I've gotten prompt updates as each new Android OS version has been released. This is similar to the experience that iPhone users enjoy.
Some devices, such as the HTC Hero and the Motorola Cliq (and the HTC Magic in certain regions), are not Google Experience phones. These phones were released with heavily customized software (such as HTC's Sense UI or Motorola's Motoblur). These customizations, while attractive to some users, also make it much harder for the phone manufacturer to update to a new version of the base Android OS. Both the Hero and the Cliq shipped with Android 1.5, and I don't believe that there are announced plans to update either to 1.6 (or 2.0, for that matter).
At first, I thought that the notion of a Google Experience phone was silly. At the time, the Magic was launching on Rogers with Exchange support, and that somehow disqualified the phone as being a Google Experience device. I now understand that Google Experience really means "unforked code base". In order to add Exchange support, I suspect that HTC had to fork and modify the standard Mail app. While they were able to add a feature that people wanted, it really just makes these phones into some sort of mutant Android device. No thank you. Google should really make it clear to users that the Google Experience is a feature in and of itself.
Android, at this point, is a rapidly evolving platform. Google Experience phones seem to be the best way to keep up with this evolution. I was pleased when I heard a Verizon rep say that the Droid will be a Google Experience phone. Now they just need to release a T-Mobile US GSM version, and I'll be happy. Over time, Android evolution will slow down, and then it might make sense for a manufacturer to fork the Android code base. Maybe they would even be willing to contribute back to the core distribution. But, until then, I'm sticking with Google Experience devices.