Very good, would recommend for the price IF you want an mp3 AND and mp4 player. The video player is good, but her is some very useful information:
Mp3 playing: I would recommend making a folder on your own for your music, but it will separate the songs by album and artist if you choose. Just to keep it organized, making a separate folder is very useful.
Mp4* playing: This is where it gets complicated, since it doesn't play mp4 files to my knowledge. It took a lot of struggling to figure out, with very little help. But I figured out that you DO NOT have to change the measurements/size of the videos, only the file type. Just change your mp4 videos to AMV videos online, there's some good website for this, but make sure you don't move around your device too much, or the device might go out of connected mode, if it does, just unplug and plug it back in real quick. After you put the AMV files into a custom video folder (Just create a new folder and title it video), you're done. Be warned, the video quality isn't amazing, and the videos are sideways for some reason, but ig they did that so it would have more resolution, but again, it's very good for the price.
I hope that anyone who buys this will learn from my experiences, and once you figure it out, it's actually not a bad device at all! You can even buy a mini Bluetooth audio jack connector to listen to music with your Bluetooth earbuds.
Oh yeah, also only one of the earbud sides works, but idc about that a whole lot :/