I had seen outstanding professional reviews published for this product for a long time, but I had been fairly content with the Plantronics 610 model I had been using. When I saw the price for the SM100 had dropped about 75 percent, I finally took the plunge.The SM100 headset is very light, comfortable and attractive, albeit a tiny bit thicker than I expected. Everyone I've called while using it has so far been pointedly amazed by the sound quality - that is, once I set the headset to its "Environmental Mode." Prior to my use of that setting, every caller complained that they could hear their voices echoing. Keeping the headset in Environmental Mode is a very simple solution that achieves incredible results, but it does present a couple of small drawbacks. First, the setting drains a bit more battery power. Second, it generates a very mild hissing that can only be heard in the headset user's ear, and which is nothing more than a bit of white background noise that is extremely easy to get used to and ignore.My more serious complaint is one I never saw mentioned in any of the reviews I had read: This headset has no redial feature. So if you're like me and tend to call the same number repeatedly, you cannot accomplish that by pressing any of the buttons on the headset. You must instead either press the redial function on your phone or go through the headset's entire "hands-free" process, which on my phone is quite tiresome and unreliable.But I think those are minor quibbles to which I have quickly adapted. This headset is generally a remarkable piece of technology that accomplishes its primary functions incredibly well.