Having both a 770 and a Zaurus 3100 (plus other present and former Zaurus models), here is my take (use at your own risk).

The Nokia is a generally fun device for web browsing. The larger screen makes a difference. Built in wi-fi avoids having to remember to bring along a wi-fi card. It integrates really well with the stowaway bluetooth keyboard. The Nokia has a vibrant developer community. It is great to see gnumeric and abiword ports progressing. The nokia is my preferred nethack platform. I think the Nokia is going places.

I plan on keeping both devices. The Nokia is fun, has great potential and I want to see how it progresses. I also tend to reach for the Nokia when browsing the web from my couch. However, if I could only have one device the Zaurus is the one that stays. Maybe this is because I am more comfortable with the Zaurus?

With respect to the Zaurus, I love the clamshell form factor and a built-in keyboard for on-the-go entry is essential. Out of the box USB host is great (although can't power hard drives). Expandability via both SD and CF is a plus. It is great having not only a built-in microdrive, but also being able to plug in a 8GB Seagate CF drive.

The zaurus has a wide selection of apps -- perhaps owing to its maturity. For operating system, Cacko with qt-embeded is a good way to go.

However, I have been using pdaXrom (X11) of late. What impresses me is the ease with which the community compiles apps for pdaXrom. Granted the apps aren't custom tailored for the display size, but they are generally pretty useable. Also, the apps aren't restricted to a single toolkit. I can run gtk, qt, wx, and fox apps.

For pim apps, the Zaurus offers platform independent versions of KOrganizer and KAddress Book which at the moment seem to have more functionality than the gpe pim apps.

For ebook apps, while fb-reader has many features I like, at the moment opie-reader seems to support more file formats. Plus fb-reader is also available on the zaurus.