The Palm web site says you need an accessory backplate to make the magnetic attachment work, so there's no extra weight if you're not interested.

There are many people who still hate the iPhone's lack of keyboard. There are many people who hate AT&T, for both political and practical reasons. There are many people who hate Apple.

I think that you're right that iPhone will continue to have the largest sales numbers. But it still remains that they have virtually no competition.