It's hardly a PDA. All it can do is play music, videos and surf the 'net. You can't enter a memo, you can't type up anything significant, there is no e-mail client, etc. etc.
Unless you can freely add third-party apps to this thing it's a nice looking piece of crap. It's basically a regular iPod with a web browser and WiFi (and less storage space). The only hope of this thing ever being used as a PDA is if it can operate nicely with Google Docs (and even then you would need a WiFi connection). For that price I may as well just get a regular iPod with a much larger capacity (big hard drive instead of small flash) for music and videos, because I would still have to carry my Z or another PDA around to actually do anything.
The only purpose I could find for this is browsing the web while sitting comfortably on a couch or something (ie use it as a mobile internet device).