I just bought an n810, mostly to replace my Zaurus SL6000L. The Zaurus is fine -- it's the most reliable device I've owned -- but batteries are hard to come by.

I've been very happy with the n810:
the interface is snappy;
it plays audio and video fine (for the latter, I just used Handbrake's default iPod-lowres settings, but switched the bitrate to 350 kbps);
caching maps with maemo mapper is great, and waiting for a GPS fix doesn't bother me so much;
carrying around thousands of pdfs of scholarly articles is incredible;
having rsync, ssh, and vim is a joy -- and being able to plug it in using the usb cable and mount the memory cards is also a joy;
claws mail is fine, I think -- though I haven't tried sending mail yet.

All I miss from my Zaurus is a flexible audio recorder, but I haven't looked around carefully. (The Zaurus recorder lets you adjust lots of settings.)

Really, vim, pdf viewer, decent html viewer, ssh, and rsync make me a very happy camper.

Maybe my standards are low!

Best wishes, brontide!!!
--Helen's Dad