I believe there is stiall a free version of paltalk (IF YOU CAN LIVE WITH POP-UP ADS).

Second Life has far better sound quality, but it takes patience to figure it all out. Free version works fine. SL music is usually done in a "concert" format (shows are usually an hour) rather than "open mic" format. Another huge feature of SL is the ability to "jam" in real time with others using the voice chat feature. People also "chain" performances from one to the next allowing a mix of several musicians o be recorded.