"The Palm Treo holds very tightly to the QWERTY and square-screen design that has marked the series since its beginnings. It features a 320-by-320-pixel screen, larger battery, and thinner overall profile compared to the outgoing Treo 750 model.
Besides more pixels, the Treo Pro screen is flush, instead of recessed into the device as with previous models. However, it is only the digitizer which is flush. The actual screen still is recessed, and this arrangement can be disorienting some times.
Under the touchscreen sits the green and red call buttons, the directional pad, and four application buttons. Like the screen, the application buttons are flush to the rest of the device, but the directional pad and call buttons are pronounced enough to feel and use easily. There's a nice glow to the call buttons too -- not too bright in the dark, not too dull when in direct sunlight.
Below this is the QWERTY keyboard. The keys keep the same straight-face arrangement that Palm's Centro line has, but there is more spacing between the keys, accounting for the wider device.
I personally think that the gummy feel of the keys is the worst of any Treo ever; I've had several female friends tell me that they love it better than anything else as they keys work great with their nails. I'll leave it as a toss up to personal opinion there.
The rest of the device is similar to the minimalist design approach taken by Apple and HTC. The left side of the device has flush volume up/down buttons and a customizable third button. The right side of the Treo Pro has the Wi-Fi on/off button -- nice touch there. The top has the power and ringer on/off switch. And the bottom has a not-quite-standard mini-USB slot, 3.5 mm headset jack, microphone hole, and stylus." Read more here: