I currently have a Treo 700wx from Alltel (had a Starcom 6700 just before that) and have no desire for an iPhone. There are a few deal breakers for me. First is that as of yet we have no Exchange syncing. If it can't sync email, contacts, appts and tasks over the air it is useless to business users. Next is the lack of a fast data connection. I know that Apple and AT&T love to say "but it has Wifi", well that doesn't help me 90% of the time when I need the data services of my phone.
Now for the big killer. I have had a "smartphone" for about a year and a half now. When I first got it I was amazed. I could call people, email, browse the web, listen to music, watch videos, check the weather, ssh to servers, ect all from one device. Now, down the road I simply don't use most of those extra features. I simply want a device that makes calls easily, gets my emails quickly and syncs with Exchange. The rest just doesn't make much sense anymore. Browsing the web (no matter how nice the browser) isn't fun on that small of a screen. The Tree 700wx has hit the nail on the head for me. Palm has a great phone.
