I was amazed at how good the sound quality was via bluetooth on my iPhone 4. When I first connect via bluetooth to listen to music, it stutters 2-3 times and then plays flawlessly thereafter. I have more problems with the phone plugged in via the USB port than with the bluetooth. The only problem I dont like with the bluetooth connection is that I cant manually select songs, I have to just scroll through them. I guess I should use the headphone jack port but then it wont charge my phone...