First up, lets talk about the form factor. This unit is much more comparable in size to my Nokia 5560 than a Palm 5 or Clie. About the same length,a little thicker, and maybe half again the width. You'll find it a little thicker than a Palm 5, but also a bit narrower. What really makes the unit stand out is that its screen does this sweet little flip thing to reveal a thumb keyboard that is actually usable.
The interface is usually a little wheel (which can be clicked as a button as well), a 'Back' button, a jump button, and a menu button. When the screen is flipped out, you have a keyboard as well. The interface largely revolves around a sort of spinning menu which quickly rotates to select your application (Calandering, Photos, Phone Calls, etc). It's surprisingly usable, but I did notice a few glitches- for example when trying to mail a picture, I couldn't return and send the picture... I ended up having to actually go to the pictures, and choose mail picture instead of writing an email and attaching it there.
I might as well mention it: the little $30 camera attachment is just a novelty. Its postage stamp sized pictures are amusing, but practically worthless. Thats probably fine with just 16 megs of memory on board anyway- you wouldn't have room to store a nice 1024x768 image anyway... I think it was more proof-of-concept in this model. And the concept works, so with any luck, a year or 2 will give us a HipTop with more memory and higher res.
The screen itself warrants mention. First off, it is a 16 scale of grey, backlit job that really looks quite stunning. Without going to a color screen, this is quite simply the nicest looking screen I've seen on a handheld.
I found the cel phone functionality to be quite usable. Rings have custom tones, and the sound is that multichannel stuff that sounds really silly thats all the rage with the kids these days. You can use an external ear thingee, or use it in the standard carcinogen position. Reception was fine, but may vary for you depending on how good the GSM network is in your area.
The web browser was also surprisingly functional. Typing in URLs on the built in keyboard is quite quick. Far faster than any graffiti handwriting recognition crap. It rendered the pages I looked at without trouble, although big graphics are quite slow, and requires some scrolling. Slashdot in light mode worked fine.
The PDA functionality is good. Contacts are interconnected with the cell phone functionality. You can use the calandering and TODO tools to keep track of schedules.
The unit also supports POP mail servers. This worked without hitch and was quite nifty. IMAP support would be nicer, but I suspect that it would be horribly slow over the phone's internet connection. There also is IM functionality, but no IRC.
There are a few nifty little games you can play as well. The form factor of the device is fairly similiar to a Gameboy Advanced, and when held in that position, makes a reasonable gaming platform.
Danger says that the phone can auto update itself as new features and bug fixes become available, so hopefully new and exciting features will roll out pleasing users with improved user interface.
Battery life is claimed to be 8 hours in use. I never managed to drain it, although I left it on quite a bit. But its still enough to easily make it through a day or 2 depending on your usage.
The thing to remember is that this thing costs just $200. FOr that you get a fully functional PDA, and Cell phone. You get a good keyboard, a web browser, and a remarkably bright screen. It's a little larger than a cell phone, a little smaller than a PDA. All in all, this is a great combination and one thats easy to recommend, especially at this price. If you have GSM network support in your area, this warrants a serious look. If the next generation adds a color screen, IRC, IMAP support, and maybe shrunk things just a little bit, I think this could truly have the integrated cellphone/pda I've been waiting for. Now if it just had 20 gigs of memory, we'd be all set. Course my fingers aren't crossed.