By negative feedback do you mean people emailing you, or any automated metrics you're using? Are you guys doing some sort of A/B testing on this?
I find it terribly annoying when I open multiple tabs and one of them starts playing anything and I have to find which one is the culprit. And when this happens I usually leave the site immediately. IMO it would work better without the autoplay by default, allowing it to be turned on using a very visible play button at the right side of the list or something like that.
By the way, nice project, I love the idea. I once used a site called muxtape[1], and all I hope is that you guys don't have the same fate they had.