"Grows on you..the more you use, the more you love!"4.5 starson by fester58
Pros: Bluetooth synch (sound/phone), sound quality, battery life, USB charger, light weight, build quality, works without battery if used with audio cable, around ear design will keep ears warm in cold weather!
Cons: Peak Volume level, may become uncomfortable if worn >2 hrs, cheap carrying case
Summary: Highly recommended. Loaded with extremely useful features. Wireless/bluetooth function sets it apart from the rest of premium headphones out there. Sennheiser did a good job researching usage model for these headphones. These work like a regular headphones if used with audio cable plugged in to the source. Batteries required for noise cancellation, SRS and bluetooth operation. I found it's sound quality better than Bose QC15 but noise cancellation is not that useful during long plane trips. Also, the peak volume level isn't enough and definitely leaves something to be desired.