Best there is
This this is great! If I don't have it on my ear but it's turned on and I answer the phone from my physical phone the call doesn't route to the earpiece till you physically put it on your ear.
Comfortable, 6hr or so battery life, it can be turned on and connected to your phone but unless you have it on your ear it won't pickup the call, Crystal clear audio coming out the earpiece, people say I sound as crisp on it as my Nexus 6 mic; Extremely comfortable
6hr battery life is about the only thing I can think of; However 6hr battery life is nothing to scoff at