I had an opportunity to play with the Droid yesterday (thanks to @ericfriedman). It was an overall positive experience. But, it felt like the user experience was missing a final coat of polish.  Here’s one small example that is very typical of the whole Android experience.

When using an iPhone, there is only 1 physical button on the face of the device, the home button.  This button always does what it says: takes you home.  Why does 1 dedicated button with consistent action matter?  Because it means all the available choices for interaction must be visible on the touchscreen.  In HCI terms, all interaction choices have a visible, explicit affordance.

By contrast, in Android there are 4 face buttons: back, options, home, and search.  Many interaction choices are hidden behind the options button.  So, I often found myself staring at the screen, asking myself where XYZ feature is, only to find it hidden behind an options button click.  But, that experience was not consistent it that the choices behind the options button changed based on the mode or app I was in.