The best AlphaSmart is still the Dana, though. The closest thing to a PalmOS laptop and everything that makes it an AlphaSmart, too, with the same great keyboard and "typing" feature.
The Dana touchscreen isn't as contrasty, the backlight eats battery, and if you use up all your batteries you will lose your data without backups. It's all quite manageable of course (since as you say it's just a Palm PDA with a keyboard) and has much more functionality, but not as bulletproof.
(I'm just happy to participate in a Alphasmart discussion LOL.)