This is a decent idea. However, the judge system has the advantage of keeping the competition about the music rather than just a popularity contest. I'm afraid that with an upvote system, many of the beats won't be heard at all, because people will tend to just listen to the submissions from the artists that they follow and upvote without listening to all of the other tracks. At least with the judge system, everyone gets an equal chance to be heard.

Just my two cents. I do like your idea though. There might even be room for both contents on steemit as the platform continues to grow.