When you power up the Treo, you see the first visible indication that the Palm operating system has a new corporate owner: After the round orange Palm logo, a blue Access logo appears.
Next up, on the Cingular model, is the default phone screen with the default Cingular logo as its wallpaper. The bottom of the interface, however, has changed: Instead of four rectangular buttons with text that send you to your contacts, call log, voice mail, and the like, you see tabs with simple icons. I found the icons a bit cryptic at first, but I quickly adapted to not having the text cues.
Some go to the same places as the old buttons--tapping the human figure brings up contacts, tapping the list icon shows call logs, and tapping the phone keypad brings up--surprise!--the soft phone keypad. A new star icon brings up a useful, customizable list of Favorite buttons that can launch an application, send an e-mail or text message, initiate a call to a specific number, browse a specific Web page, or even show how much you owe on your Cingular bill or how many minutes you've used out of your monthly plan allocation.
And I really liked the 'Ignore with Text' phone feature introduced with the Treo 700 models: You can opt to answer an incoming call with a text message, which can be very useful if you're not able to talk but would like to give the caller something more personal than your standard voice-mail greeting.
Like previous Treos, the 680 is more usable as a phone than many other PDA hybrids. It's reasonably comfortable to hold to the ear, in part because it's not as wide as many competitors (2.3 inches, compared with, for example, the 2.8-inch width of the Nokia E62). I found the voice quality decent, and the volume seemed somewhat better than the 650's. The integration with Palm contacts remains a strong feature; the five-way navigation button lets you easily initiate calls with one hand, whether you're working from an address book entry or the call logs. (We have not yet lab-tested the Treo 680's talk-time battery life; check back for a full review.)
People who send a lot of text messages will appreciate Palm's threaded chat application for this sort of communication, which displays exchanges much the way they would look in an instant messaging application.