I'm using the 7506s. They are MUCH better at isolation than the Yamaha RH3s I was using, but I still get some bleed. Not bad though - main problem is metronome click bleeding through at the end of a track. The Sony's are a bit uncomfortable for me after a long tracking session - the coiled cord is annoying - they fold up on you when you take them off - but I like them ok. The sound is good and the isolation is acceptable. Gonna try the Senheiser HD280s next.