I recently ordered the GPD-WIN, which is a pocket PC made for gaming. It can run a wide range of emulators from the NES to the Game Cube and Wii, as well as PC games. There are even some modern titles, like Fallout 4, that run at playable framerates! The GPD Win has an Intel Atom x7-Z8700 quadcore Cherry Trail processor, 4GB of RAM, and 64GB of eMMC 4.5.1 storage on board. Memory can be expanded using micro SD or using a flash drive in the USB 3.0 port. It also has a fan with a physical switch for varying speeds. The fan noise is pretty low.
Here's a good review/breakdown of the unit. This reviewer ended up overheating his unit, doing some benchmark tests, and fried the keyboard. GPD offered to replace it for him.
My impressions:
-Could not get over how small this thing is. I've used a GPD XD before and watched lots of videos, but I was still floored that I had such a small, fully-functional PC in my hand. Just so cool!
-Very surprised by the build quality of this thing and even the packaging that it came in. It doesn't feel like something that cheap and reminds me of a product that a big gaming company would release.
-The d-pad is a little mushy but seems OK enough for most games. The should buttons feel pretty good and controlling the mouse using the analog stick and the shoulder buttons works really, really well. It's also nice to have touchscreen functionality, too. The keyboard is fine for what it is, but forget about doing any real typing on it or playing games via kb/m. Should be obvious that if you want to do that you'd want to plug some in, though.
-Where the d-pad falters is with fighters. I'm having trouble pulling off special moves consistently and you have to press hard to make sure motions are registered. Maybe it just needs to be broken in. But the good news is that the left analog nub works
amazingly well. I usually detest using analog sticks to control fighters, but I had no trouble with this one. It almost reminds me of a NeoGeo CD pad, just without the clickiness.
-This unit is roughly the size of a 3DS XL but is much more comfortable to hold and use. The 3DS XL always tended to cramp my hands...this does not.
-Had the Intel HD graphics crash on me, several times in a row, when Steam was running and I tried using Windows search. I restarted explorer.exe and it was fine again. I spent a good 30+ minutes messing with SFV and it never crashed. Played with the fan on. Also noting that I disabled the touch service before playing it. That's an issue on the Surface and it is possible that it may crash some other games if it's not turned off.
I'm also nerding out so hard realizing that you could hook this up to a TV or monitor, plug in or pair it with controllers, and use it as a micro-console. Who needs the NES Classic Mini now?
Hardware pics:
(Note that the units that are shipping now have the Intel Z-8700, not the 8750 -only initial units had it- but from testing, people are actually finding that the 8700 works better!)

The USB port is now 3.0. "TF Card" is micro SD. And it also now uses USB Type C for charging.

Games I've tested so far:
ULTRA Street Fighter IV: Will run above 60 FPS at 1280x720 if you turn the background detail to low, which means no backgrounds. If you use a lower resolution, you can turn it on high and it will run great. At 640x400, the game gave me a benchmark well above 60 fps and I could run the game with more settings on high. The lower resolution isn't so noticeable when you're playing. Looks 1000 times better than SSF4 on 3DS.
Street Fighter V: Doesn't run well enough on this to be really playable. Kind of amazing that it DOES run, though. Even at the lowest possible resolution -200xsomething- couldn't even tell because the text was too
Skullgirls: Turn backgrounds to 2D and the game will run perfectly at 1280x720. Looks absolutely
gorgeous on the screen! Much, much better-looking than the Vita version and the load times are insanely fast. A standout game on the GPD WIN to me, so far.
DOA5 Last Round: Looks gorgeous, but...nope. Couldn't get it to run at 60 FPS and the game won't let you go lower than 1024x768 for some reason, nor can you run that setting in full screen.
Saint's Row The Third: Wouldn't launch. Have read there's problems with it on Windows 10. It works just fine on my Surface, though...
Melty Blood Actress Again: Current Code: Runs perfectly at 1280x720.
Mercenary Kings: Runs perfectly at 1280x720.
Shantae: Risky's Revenge: Runs perfectly at 1280x720.
The King Of Fighters XIII: Runs perfectly at 1280x720. Just want to add that I couldn't run this game this well on my older ASUS tablets from just a few years ago. Pretty awesome seeing it on the small screen in such a perfect state!
Pac-Man Championship Edition 2: Runs poorly. Unless I missed something, there are no configuration options. WTF?
Mighty Switch Force! Hyper Drive Edition: Runs perfectly at 1280x720. Like Skullgirls, this is a standout title visually. Pops off the screen.
Trine: Seemed to run well with v-sync off and with graphic detail at medium at 1280x720. I want to try it again with lower detail settings and see if I can get it a bit smoother.
Outrun 2006: Coast 2 Coast: Runs great at 1280x720. Noticed a little bit of stutter here and there, but otherwise seems to be running at 60 FPS. (I really need to put FRAPS or something similar on here!)
Resident Evil 5: Runs at 25-30 FPS (avg 30 fps) with settings on low at 1280x720, per the benchmark test. At 800x600, it runs well above 30 FPS and gets framerates in the 30s-50s. It looks great this way but is 4:3, so will stick with 1280x720 instead.