PocketCHIP is the pocket sized Linux terminal I always used to want. Which is to say, it runs (nearly) stock Debian, X, etc, it has a physical keyboard, and the hardware and software is (nearly) non-proprietary and very hackable. Best of all, it's fun and it encourages playful learning.
It's also clunky and flawed and constructed out of cheap components. This keeps it from being something I'd actually carry around in my pocket and use regularly. The smart thing they've done though is embrace these limitations, targeting it at the hobbiest, and not trying to compete with smart phones. The PocketCHIP is its own little device in its own little niche.
Unless you're into hardware hacking and want to hook wires up to the GPIO pins, the best hardware feature is the complete keyboard, with even Escape and Control and arrow keys. You can ssh around and run vi on it, run your favorite REPL (I use ghci) to do quick programming, etc. The keyboard is small and a little strange, but you get used to it quickly; your QWERTY muscle memory is transferrable to it. I had fun installing nethack on it and handing it to my sister who had never played nethack before, to watch her learn to play.
The screen resolution is 480x272, which is pretty tiny. And, it's a cheap resistive touchscreen, with a bezil around it. This makes it very hard to use scroll bars and icons near the edge of the screen. The customized interface that ships with it avoids these problems, and so I've been using that for now. When I have time, I plan to put a fullscreen window manager on it, and write a pdmenu menu configuration for it, so everything can be driven using the keyboard.
I also have not installed Debian from scratch on it yet. This would be tricky because it uses a somewhat patched kernel (to support the display and wifi). The shipped distribution is sadly not entirely free software. There are some nonfree drivers and firmwares. And, they included a non-free gaming environment on it (a very nice one for part of the audience, that allows editing the games, but non-free nevertheless). They did do a good job of packaging up all the custom software they include on it, although they don't seem to have published source packages for everything.
(They might be infringing my GPL copyright of flash-kernel by distributing a modified version without source. I say "might" because flash-kernel is a pile of shell scripts, so you could probably extract the (probably trivial) modifications. Still.. Also, they seem to have patched network-manager in some way and I wasn't able to find the corresponding source.)
The battery life is around 5 hours. Unfortunately the "sleep" mode only turns off the backlight and maybe wifi, and leaves the rest of the system running. This and the slightly awkward form factor too big to really comfortably fit in a pocket limit the use of PocketCHIP quite a bit. Perhaps the sleeping will get sorted out, and perhaps I'll delete the GPIO breakout board from the top of mine to make it more pocket sized.