My neighbor has a Clie PEG-TJ37 and he says that it great although I've never tried it. It doesn't have an integrated keyboard though. Personally I think that once you know all of the text commands, writing using that method is pretty quick and easy. And PalmOS is nice and stable with a good list of available apps.
I'm thinking about buying an iPaq H4155 in a few months myself. I've been on a 6 year journey with Palms and Clies and now, I think I'll try something new.