On the strength of the very high rating and huge reviewer feedback here on Amazon, I bought this Bluetooth device -- my first bluetooth headset ever. I finally have a phone that has Bluetooth capability, and I was keenly interested in a wireless headset that wouldn't have the cord tangle issues of corded headsets.This device does exactly what I wanted it to do. It was a piece of cake to setup on my Verizon Samsung u540 phone. You wouldn't even need to crack open the user manual except to discover the 4-digit code you have to plug-in to your phone (it's 0000, btw). After that, it's a snap to turn on and link to my phone.My other important concern was voice clarity, both on sending and receiving. Thus far, after several hours of use, I can tell you that the voice reception I hear is crystal clear. No crackling, no hollowing or echoing. On the other end, I've not had anyone complain about being unable to hear my voice or that my voice is coming across muddled -- interestingly, I've had such complaints while using my old, corded headset!The power button *is* small and it *is* a tad more difficult to depress than you might want, but then, you won't accidentally turn on or turn off this device because of the way it's designed. I agree with others -- turn on the device before putting it on your ear, and do the same when you're turning it off.As for noise canceling, my wife and I tested out this device in very noisy home with four small kids, and I was very pleasantly surprised at how well this headset communicated my voice but not the ambient noise in the room.Using the volume control on the headset was pretty easy to do. Note that you can control voice volume either through the phone handset volume control or the control on this Plantronics headset. If other reviewers are complaining about low volume from this headset, it's likely because one of the two volume controls is turned down too low, or perhaps the mobile phone their using doesn't have much by way of signal output. This Plantronics headset has *plenty* of loud volume if that's what you want.As for ear comfort, I found it to be very comfortable, although I haven't worn it all day long. I talked to a friend for an hour yesterday, and I had absolutely no discomfort at all. The device comes with three earpieces (small, medium and large). I use the medium with great results.The phone fits snuggly on my ear and it doesn't move around at all, although I'm not jogging or even walking much while using it.I like the more discreet look of having the "guts" of this device behind my ear, with a thin microphone on the side of my face, rather than the fat Motorola designs.Other reviewers have cautioned about the headset breaking, so I just take very gentle care while handling it. I suspect I won't have a problem with it falling apart.I can't speak to battery life, because after a lengthy phone call, I just recharge it so it's ready for the next call I might make. Charging it is easy to do and doesn't take long, either.In sum, I'm very satisfied with this device. As long as it doesn't break, it's performance and comfortable design make this an excellent choice.