Hmm. Not "usable" in the way folks on this forum would normally describe it. Let's see...

-- This device ships with Debian Linux. If you order a PocketCHIP, it includes a "GUI" that shows six icons for six demonstrator apps: Terminal (access to the terminal), PICO-8 (a game engine), SunVOX (a music creation app), Help (an HTML page), Write (Leafpad), and Browse Files (a file manager called PCManFM). There's also a limited settings screen. That's it.

If you order the CHIP SBC by itself, you get no GUI at all. (Of course, you can install your own.)

I've pretty much stopped using the PocketCHIP GUI, and just use the terminal to manage the device. Then again, that's kind of what I prefer.

-- The PocketCHIP's screen resolution is 480x272 pixels, so many ordinary apps are going to have trouble fitting onto the screen. (Although Firefox does quite a good job of using that space effectively. I was kinda surprised at that. )

-- They don't yet have a driver set up for the Mali GPU. So, videos and gaming are extremely limited. NTC says that they are working on this; but no precise timeline (that I know of) yet.

-- The CPU is pretty darn slow. Of course, I'm mostly running desktop apps on my machine; but then, that's pretty much all that's available right now.

So if you're looking for a portable experience akin to an iPhone or an Android, you'll want to look elsewhere.

I'm doing fine with it, though:

++ So far, I like the keyboard (although lots of other folks complain about it); the size and the tactile feedback feel very nice to my thumbs. Editing files in vim is quite nice.

++ But, if you don't like the keyboard, a bluetooth keyboard will work just fine -- I tried it myself. Or, even easier, just plug a USB keyboard into the provided USB port. I've tested that too. (A mouse works too!)

++ Along those lines -- probably the easiest thing to do is to just plug a USB hub into the machine. The PocketCHIP can only provide a limited amount of juice to external peripherals, so a powered hub is probably best. I've still been messing around with this, but I'm probably going to set up a permanent "dock" for my PocketCHIP, so that I can use my favorite keyboard and mouse with it. Works with USB hard drives as well. I guess pretty much any USB device that works under Linux will work on the PocketCHIP...

++ The PocketCHIP's network settings app was too limited for me (I couldn't set a static IP address). So, I simply went to the terminal and ran nmtui; voila, network up and running. It really is the full-blown Debian distribution.

++ The battery is lasting me longer than I would have expected (hours even!). But, I have to admit I've not tried to completely drain it yet. My personal use-case so far has been to treat this thing as an extremely portable desktop computer that I'm using at various static locations, rather than something I use while in transit. So I end up having it plugged in most of the time. Still, it's the best I've seen any SBC do in power management yet.

In sum: this is a single-board computer housed in a fairly convenient portable case. If you have a reason to take a single-board computer around with you, this thing is delightful. If you just want to run some portable apps while on the go, this thing will be useless for you.