Hello! I'm a current Palm and PPC user. I'm also a former Clie user who misses the thumboard on my TG50.
I think that you'll really like the 4355. It's a nice device with a really good keyboard. As far as I can tell from the forums. there were very few complaints about this model.
Except for the lack of landscape support I can't think of anything significant that you'd be missing by not having WM SE. (I have a 4155 and have loved it.)
Good luck with your decision!
TMann
