Pros: * 4xAA batteries for the console. 2xAAA batteries for the wireless controllers * Comes with 2 infrared controllers but range is good due to multiple lights being used. * SD slot for game backups * Okay sound and okay display. Some clones are much worse. * Some people dig the Sonic look. I could care less.
Cons: * Most likely emulation instead of clone hardware. * No save games! * They tried to make the controllers look like the Wii joystick bar thing.. Just awkward to use. * GAME folder on SD card doesn't appear to support multi-level folders. This means lots of scrolling to get to your game of choice.
Did not try: * Loading ROM over traditional sizes like 8 megabit. Last clone I did this with destroyed it.
I've got a couple of AtGames handhelds - the major issue most people have is not game compatibility, but the FM pitch being off, so music doesn't sound right. If you can ignore the music being off-key, the emulation isn't that bad. We've seen worse on the PC.
I seem to remember there being a list of games the AtGames emulation doesn't handle right over at SEGA-16 in one of the many threads on AtGames consoles/handhelds. Many universally revile the AtGame for the off-key music. I think it makes a decent cheap console/handheld for the kids as they are cheap - if they break one, no big deal. While you can get a "real" Genesis cheap as well, people get more upset if someone breaks it.
I agree that the single directory for games on the SD is irritating. I keep all my games sorted into sub-directories to make it easier to find what I'm after. I try to keep the SD card in my AtGames handheld down to just the games I want to play, not everything because of that issue over sub-directories. There was a thread on SEGA-16 about a new database for the SD card to show icons for all the games. That's handy - you might want it for yours.