To put it bluntly, Atgames Genesis products suck. Whether it's the XX-in-1 consoles, or the handheld devices, they just can't get it right. The video is serviceable, but the sound is always horribly off, and there are even glitches at times while playing. The company simply can't seem to make a solid Genesis clone to save it's hide.
So yeah, avoid it. If you don't believe me, hop on YouTube and look up some reviews that actually have someone playing the games. It makes even early Genesis EMUs look better by comparison.