Good but lacks some simple but important features.
To earn points you have to coordinate your left and right hand to make the correct input. Concentration is the key to success.
There are four difficulty levels. Forget about the easiest - it will put you to sleep. For me the second hardest difficulty is the most fun because it goes best with the music and doesn't make my head go boom.
Additionally there is a Jam Session mode in which you can work with a set of loops to create new mixes. It's cool and relaxing but won't hold your breath for too long.
Now let me list the short comings of Beats. They really hurt because they would be so easy to fix and would have such great value.
* You cannot have play lists or shuffle through a folder. Every time a song ends, the menu loads again and you are back at the beginning of your song list. Since you have to do this every three minutes the loading time seems quite long and scrolling through the songs also takes some time. The flow is totally interrupted.
* You cannot see all your files if there are too many in a folder. I have most of my songs in the main folder. I can only scroll through a tenth of them. The others are simply not shown.
* There are problems with none-ascii characters. I cannot play my German songs with mutated vowels in the title. Maybe it's just a coincidence but the vowels can't be displayed either. So I think that's the problem. 21th century, hello?!
* There is no shuffle mode for the visualizations. There is a ton of different visualizations but unless you go back to the main menu and into another menu to switch your current visualization you will see the same one over and over again.
* Songs are not balanced point wise. Short songs have less potential points than long songs and fast songs have more than slow songs. It renders the high score list useless.
Beats is still well worth its money and it gets bonus points for letting you use your own music. It would be cool if there would be more games like that but since you cannot sell new song packs for such games the industry probably won't support that idea a lot.