My existing headset looks just like a Plantronics audio 650 USB, but I don't have the USB dongle for it. I have used it with Skype and to narrate online tutorial videos. When I purchased Dragon NaturallySpeaking 10, I wanted to increase my accuracy so I purchased this noise-canceling Sennheiser microphone.
Out-of-the-box looked and felt great. The EQ is a bit odd, like other Sennheiser headsets I've owned in the past; I like it though, because it makes rock music sound great.
Unlike my Plantronics headset, the ear muffs are foam and let my ears "breathe" a little, which keeps them from getting too hot. It is also very comfortable even though I wear it for hours at a time.
The microphone is a completely different story. My voice sounds tinny and the microphone picks up WAY more background noise. It doesn't seem to make a whole lot of difference with Dragon, but it is definitely worse for Skype, and there's no way I can use it to narrate videos.
I like the Sennheiser sound, but this headset is not at all acceptable as a noise-canceling mic. I am disappointed because I basically wasted my money. Considering that the Sennheiser mic costs about 50% more than my Plantronics, I'm a little disgusted at the outcome.