I own a GCW since this week, bought it in mint condition for 115 euros shipped from abroad.
Here are my impressions.
The size is excellent, this is a handheld that you can take with you: not as small as the Wiz/GBA micro, not as big as the GPD XD.
The handheld is very light.
The 3,5 inch screen is a great 4:3 size screen.
It is awesome for Genesis, Snes and PSX emulation. Also for Neogeo and GBA.
The d pad sucks.
The handheld feels a bit cheap because it is so light.
The PC engine emulator has no vsync, so that makes it worthless.
FBA: Hmmm. Neogeo, cps1 and cps2 are great on FBA. But why won't regular games like Shinobi, Tetris (no sound), Raiden DX and all those Irem M72 games play on it with full speed?
Mame: luckily this plays Shinobi, Rolling Thunder, Tetris and more but no Irem M72 games.
I am 75% satisfied with it.
The things I would change is:
Better dpad, better buttons, better pc engine emu and better arcade / mame enulation.
The things I like: really great snes and genesis emu! Better than those I have on my psp and gpd xd!