I use these, they have some promotion with Underwater Audio. They work well, I find you need to get them in BEFORE you get in the water and keep them in. Remove them and reinsert and the audio quality will go down slightly. For giant step entries, wear a hood!
Quality is OK. It certainly muffles and mumbles at bit as you get deeper. They work better than the old iDive 300's UW transducers. Rock and roll or music that needs a heavy beat to keep you in it will be interrupted by your regulator and breathing sounds. Jazz, Tranc-y electronica, Classical are all great choices.