Gamepark Holdings gp2x comes in 2 basic models. f100 (no touchscreen, digital joystick and black). f200 (touchscreen, retarded dirpad and white). both are no longer made. Software support is pretty damn good with a lot of emulators and games available. It is probably the least powerful hardware wise but certain emulators run better on the f100/f200 than they do on newer devices due to optimization over the last few years.
Gamepark Holdings gp2x wiz is a different device which is smaller and slightly more powerfull has an oled touchscreen and dirpad. f100/f200 software is not natively compatible on the wiz but a wrapper of sorts has been made which will allow you to run a lot of f100/f200 software as well as its own library of stuff.
Gamepark Holdings caanoo is the newest of the bunch and is pretty much a larger version of the wiz with an analogue nub and touchscreen as well. Software from the f100/f200/wiz is not compatible with the caanoo at this time. The caanoo is still very new so software support is pretty weak at this time.
The Gemei A320 or dingoo A320 is a different device manufactured by a chinese company that was hacked by a few people and linux was installed on it. It doesnt have a touchscreen and is not compatible with any of the f100/f200/wiz/caanoo software. That said it does have a pretty decent library of software including emulators, media players and games.
There is a lot of software that has been compiled to run on more than one of these systems so you get a lot of overlapping stuff.
The pandora was developed by importers of the gamepark holdings devices and is a completely different beast. It is basically a mini linux computer with gaming controls. It is more expensive than the others and at the moment very hard to obtain due to manufacturing difficulties there are less than 1000 out there in the wild. Software support isnt bad considering the low number available and you can use a full linux desktop environment on it. The pandora is the most powerful of all.
