So I'll play Devil's advocate here.
I purchased a Treo 650 the week they came out, as I was very excited to get my first smart phone and had heard a lot about how the 650 was *the* phone to get. As I was taking a trip across country, I figured what better way to test it. I'll leave my PowerBook at home and see how "smart" this smart phone is.
When the Treo 650 worked it was good enough, I guess. Just not great. Email and web browsing (though a little slow) were nice. But to get an email client that worked with my IMAP accounts (like .Mac) I had to shell out another $20-30. Same thing with an instant messenger. None out of the box (are you kidding me?). There goes another $20-30. So keep in mind that if you need IMAP support and want to send instant messages (who doesn't?) then add another $50-60 on top of the already pricey Treo 650. There's other software that isn't included, but those two are enough to reconsider just what it is you're buying in a Treo 650.
Bluetooth was cool to have, but syncing over BT was unbearably slow. So slow, that it wasn't even worth it after the first go. I guess it's good for BT headsets, but if you think you're going to want to sync over BT on-the-go, then be prepared to wait a while as it connects and transfers. I'll wait for the BT 2.0 phones, as they will finally provide a wireless sync fast enough to do away with the USB cable.
The phone features were well designed, but as a cellphone, it's more than a little bulky. I knew what I was getting into when I bought the Treo, so I won't harp on size. But let me just say that after a month of constant use, it's too big as your only cell phone. Period. Perhaps you could activate a smaller, cheaper phone on the same plan for going out at night. But why bother?
Oh, and the last thing. It soft-crashed *all the time.* Perhaps there've been a few updates that addresses this, as I mentioned before that I bought my 650 the week they came out. But this thing crashed, hung, froze so often - it was distressing. And disappointing for a device that cost me over $500 at the time.
Now, I know that a lot of people love their Treo's and there were some nice things about the product. This is just my experience as a new Treo/smart phone user. I returned my Treo 650 and went back to using my old T610. For my money, I'll wait for a smart phone that has the necessary software included, isn't as bulky and isn't "flakey" or prone to crashing all the time.
[/rant]