I put a couple different distros of linux on my iPAQ early on, and had a blast doing it. This was before familliar really started taking off. In the end though, I put WinCE back on it. As a result of my experience though, I have the following things to say about linux on handhelds:

1. A good GUI is a must. No matter what cool tools you put on your PDA, it is a computer for displaying information first. I played around a bit with development, and other writing/typing intensive apps, and every textual interface is slow and cumbersome. (Although for writing plain English, Microsoft's Transcriber is useable on good days.)
2. Programming in particular requires a far better user interface. How do you type <ESC> on an iPAQ? How 'bout key combos? With the interfaces I've seen, almost all the characters =~ m/\W/ were hard to get at.
3. I know this is no longer the case, but at the time, the lack of a sleep mode was a big--. To shut the thing off, I had to log in as root, and issue a shutdown command. Yikes!
4. Speaking of which, do people find it still acceptable to work as a non-root user? With so little real estate, having two windows open is difficult, and using the UI to type in a password (i.e. a hidden field) is always trouble for me.

Now granted, I'm not as current as I'd like to be here. Maybe a lot of problems I had have been taken care of. (At least one major one, the sleep mode, has been.) But with the iPAQ, I still find I prefer things like I do with its bulkier cousins. I run linux on the box that lives in my closet and, at least for the most part, Window is my desktop.

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