"Good, not great."2.5 starson by Eclectophile
Pros: Excellent noise canceling, Good sound quality. Good mic sound quality. Good battery life.
Cons: Smart sensor is easily confused, noise cancellation appears to be tied in with incoming audio which cuts off your mic,
Summary: I have had this headset for over 6 months. I spend my entire day on the phone for work and this was a great way to free up my hands, avoid a wired headset, and deal with background noise. After months of using it I have to say that most of the time it's a very decent headset. It's difficult to get decent reviews on headsets involving call quality online. All of the reviews seem to deal with features but never really put headsets through their paces. All in all this headset has great call quality on both sides. No one complained that I sounded like I was in a tunnel, the way the do with so many other headsets. The call quality on the receiving end was very good although I think the speaker is a little on the muddy side in that it seems to intentionally roll off the treble.
The smart sensor seems like a good idea however if you put it on after taking a shower, your hairs wet from rain, or if you're walking around and it's a hot day and you sweat, the sensor gets confused and will randomly transfer calls to your handset. They totally should have let the user decide if they want to keep using this feature. Maybe they did but I use a Mac and Plantronics seems to favor the PC for product support. In any case it's annoying and it happened regularly enough for me to stop using this headset as my first choice.
Finally, the biggest gripe. It appears that the engineers have the audio from the other end of the receiver, in some way, going through the noise cancellation circuitry of the headset. So, for instance, if the person you are calling is standing outside in traffic, you hear the roar of traffic as plain as day, HOWEVER, the noise cancellation circuitry will turn your mic off. You can turn the volume down to compensate for all the background noise coming through on the other side of the call. That's no big deal. But I've spent minutes talking to people and they didn't hear a word I said because for some reason their background noise was so bad that the headset cut off my mic. This is inexplicable because I've literally stood in front of a large operating diesel generator and spoke in a normal voice and the person I was talking to told me they couldn't hear the generator, only my voice. So the noise canceling tech is great, but something coming through the other end can cut your mic out completely.
So anyway, I've thrown this headset in the standby bin and I use it when I drive. This headset has some amazing features and, I'm guessing, it's only a firmware update or two away from being great. But I'll never be able to update it because I use a Mac. Way to go Plantronics. Way to alienate 10 percent of the market. At the moment, I am using a 10 dollar Panasonic wired headset and it does the job better than the 500 or so I've spent on wireless headsets in the past 4 years. It doesn't have noise cancellation but it also doesn't cut my mic off.