I have had one for a couple of days. It could be good with a hack or new firmware. As it stands, the included games are mostly junk, very weird collection especially the bonus games.
The real strength is the fact that you can put games on a SD card and play from there, but the interface is horrible (one folder, no search or listing options) and the controller doesn't always work correctly or lacks buttons to play i.e. 5200 games. The paddle controller does not work with games loaded from SD, unless the game is also in the official list. Most 2600 and 7800 games work though.
I also wished there was Atari 8-bit support but those games don't work either, not even the cartridge based ones.
More controller options, a better SD card interface and Atari 8-bit support and this would be all I need for my Atari emulation needs.