Bottom line: the Treo 650 is a superb device for Palm OS users, period. However, since it's currently only available on Sprint, I'm holding off.

PalmOne has been working on the Treo line for a while. Their Treo 600 is arguably the most popular PalmOS-based smartphone, and the Treo 650 is evidently an attempt to improve on its strengths by adding features.

First, the gross physical attributes. The Treo 650 is about the same height as the SMT5600, but it's much wider and somewhat heavier (although lighter than the 7135). The screen is large, very bright, and very sharp-- the only better screen I've seen on a handheld is on the iPaq 6315. It's physically smaller than, but as bright and clear as, the excellent screen on the Tungsten series; the screen is clearly visible outdoors and in sunlight. Below the screen are the familiar four Palm application buttons and a five-way nav device, plus "home" and "menu" buttons; below the buttons is the Treo's QWERTY keyboard (more on that in a minute).

Phone: the Treo 650 worked flawlessly as a cellphone. I was easily able to make and receive calls, and the integration between the built-in address book and the Phone applet is excellent. I had a little trouble using the keyboard to dial, just because the number keys are much smaller than the ones on the SMT5600 or 7135. For the first time, I actually found myself waiting to make phone calls in the car until I could pull over or stop and actually see what I was dialing! Speaker and speakerphone volume were both quite good. There have been reports on Slashdot, and elsewhere, of poor audio and voice quality on the Treo 650 but I didn't have that problem at any time during my tests.

Messaging: PalmOne includes two messaging apps: one for SMS messages and VersaMail for email. I was most interested in Exchange ActiveSync, so I spent a good bit of time with VersaMail. Overall, I found it inferior to Pocket Outlook in both ease of use and stability, although VersaMail does a better job of handling multiple email accounts and letting you quickly switch between them. When you configure a mail account with EAS (you can only have one at a time), the device warns you that it's going to erase all of your stored messages and calendar data, then resync. I lost my calendar data by accepting this warning, then forgetting to configure my desktop conduit to skip calendar sync-- be careful! (To be fair, this was entirely my fault, not the Treo's.) Once set up, Exchange ActiveSync worked fine, although there are no sync logs kept on the device. This would be a helpful troubleshooting feature, and I hope Palm will add it in th next release (along with sync for contacts and additional mailbox folders).

Synchronization: I had a few minor problems with ActiveSync on the desktop, but those were easy to resolve. Over-the-air sync with EAS worked well, and I like the ability to choose what gets synced over the air and what gets synced over the wire-- the Treo 650 forces you to sync mail and calendar data or nothing at all. I also tried using PocketMac Phone Edition to sync the 5600 to my Mac OS X desktop running Entourage. BIG mistake. PocketMac is unstable and buggy; their technical support is slow (when they respond at all), and the software doesn't do what it claims. Avoid.

Bluetooth: I tried to use a Jabra FreeSpeak 250 headset with this phone. The headset is listed as compatible with the Treo 650 as a headset device. This is odd, since it worked fine with the SMT5600 as a handsfree device. One annoyance that the manual didn't mention is that with a headset-only device, you have to push the headset button to transfer a call from the handset to the headset-- this contradicts the manual's assurance that when you have an active headset, calls are automatically routed to it. Fortunately, PalmOne has a KB article that explains how this really works.

Other: the Treo 650 has an integrated camera that is reputed to be quite good. My device was a preproduction test unit and didn't have a camera, so I can't say whether it's any good or not (but these side-by-side comparisons make the Treo 650 look pretty good). Battery life has been excellent, and the addition of a replaceable battery is quite welcome. The internal speaker sounds great when you play MP3s through it, which surprised me a little bit. The addition of a sliding "mute" switch on top of the phone was a very useful touch; it's trivial to make sure the phone is muted before you walk into an important meeting, or church, or wherever.

Bugs and annoyances: most of the annoyances I had with the Treo 650 centered around Sprint's service in my area; I had trouble making and receiving calls in and around my house, and for a whole day I couldn't get my voicemail. This is not to say that Verizon or T-Mobile has great coverage in my neighborhood either. I had a little trouble getting used to the keyboard, which is awfully small. I already mentioned its effect on dialing; another minor niggle was that I never did figure out how to use keyboard shortcuts for menu commands. However, with a keyboard-aware app like DateBk5, it's possible to work without using the stylus at all-- an impressive accomplishment.

In all, this is a terrific device, although at $369 for new subscribers it's fairly expensive (although, interestingly, cheaper than the Kyocera 7135 from Verizon!) I'm waiting for either a GSM or Verizon version before I take the plunge, but the screen quality, speed, and utility of the 650 make this a very strong contender as my next device.