Sorry I took so long getting back to you. www.kompos.com has had a consistently high rating over the last few years. There are lots of good ones. It was my ambition to keep track of them. Group interest in rating them has not really been there and I don't think it is necessary. Look for ones that have recent posts and genres that you prefer. Some have them all, some are more specialized, some just didn't have the interest in certain genres. Their server is important, You want a fast, rock solid, server. If they are slow or have crashing problems they are just no fun. Real time Jamming is so close we can taste it. However, there are still lots of problems with it. Software compatibility, Actual distance, it works better if you are within a few hundred miles. The endless stream of spybots and malware slow everything down. I have to do hours of maintenance every few days and I'm getting really tired of it, but it is the nature of the beast. If you find a Music Collaboration site that has a slick utility for real time jamming onsite, let me know.