I bought one of these because I'd seen the bigger version of this unit work well in conference rooms and was pleased that it plugged into my Mac without any fuss. This one is smaller and suitable for a home office worker. The critical thing about a unit like this is that it avoids echoes properly (even when there is a lot of latency on the connection) and that your voice is clear to the people on the other end of the line. Feedback on audio quality from people I've been on calls with is good. The LED that changes from blue to red when you are on mute is a nice touch, and the mute button is easy to hit. Looks a bit pricey compared with similar units but I'm happy with mine.
We bought several of these units for use with GoToMeeting. We wanted a solution to allow multiple people in an office to join a meeting once via VOIP and to be able to speak and hear clearly and with no feedback. This is the perfect solution for this use case.
The other thing that we are using these for is for people who do a lot of meetings or VOIP calls, have the privacy of their own office (or home office) and don't like wearing headphones.