This isn't a full review, but I wanted to at least get some reactions down sooner rather than later.
In general, I really like the device. I've been unhappy with the increasing trend toward smaller and smaller devices, so the size and weight seem just about right to me. The belt case it comes with is adequate and is my preferred way to carry it (since it has a sturdy belt clip and a magnetic flap that actually works), so I don't have to worry about the logistics of carrying it in a pocket.
My biggest complaint about it is probably that it feels slightly unstable. I've been having constant problems with the GPRS service only working until I plug it in for a recharge, at which point it says it is connected but is no longer actually passing data (email won't sync, DNS won't resolve) and I have to completely reboot the device to get it to work. It also seems very sluggish and slow at times, and I find myself having to reset it on average once every other day. Other than that, though, I like how it works. The keyboard is great -- I've built up a decent amount of speed quickly -- and the stylus is conveniently placed. Windows Mobile 5.0 seems a lot nicer to work with than earlier versions, and I like it a lot better than the various versions of Palm OS I've used. It's nice to have Outlook on my device and not have to worry about contact synchronization weirdness.
The wired stereo headset that came with it scraped up my ears, so I punted and got a Motorola Bluetooth headset. That's been an interesting experience worth a separate blog posting.
I suspect that I will find a lot of my problems will just go away once I find a reliable set of ROMS to upgrade the device. Once I've done that and had a chance to compare, I'll write the full review.