Macworld’s Dan Moren:
One of the things you probably don’t think about on the iPhone is probably the most basic design decision: you will operate ninety-nine percent of the phone with the touchscreen. Don’t worry about figuring out which hardware buttons you have to press to do what; almost all the controls you need are contained within the canvas of the touchscreen. This is the G1’s big failing for me. Because it’s a generalized platform, it’s not designed from the ground up for just the touchscreen. You can do things on the touchscreen. Well, some things. But sometimes you need to jump back and hit that hardware Menu button. Or the home button. Or the back button. Or you could ignore the whole touchscreen thing and use the trackball instead. That’s a lot of choices, and sometimes when it comes to users, choice is bad. If the user has to think about which interface they need—or even want—to use, for a particular task, that takes up time. An infinitesimal amount in each instance, yes, but it adds up.
From a design perspective this is right on. Also, the G1 shows what I think is one of the big obstacles to widespread Linux use: it does almost everything, but doesn’t do one thing really well.