When Microsoft Office Communications Server 2007 was first released, I was a remote worker and part of the team enabled for voice which brought with it a Jabra GN Netcom 2000 USB headset, a beta device in fact. I have used this as my primary device for the past 6 years without issue. I was provided with an update from Sennheiser which included not only a new USB headset but the DECT monoaural headset which I really enjoy, and it can also be used as an in-ear piece but I still tend to feel awkward with the device as I sit at my desk and am rarely on the go. Further to this point, I like to sit at my desk with keyboard and mouse, but have found with this new Sennheiser device I stand up and walk around in my office as well a few hallway walks. The USB headset is the SC 260 model and the DECT headset is the DW Office model and the one I use daily.
I also own a Jabra 410 speakerphone which is great but my office has hard wood floors so it creates a cave like echo for the other participants so I don't use it as much.
The new Sennheiser is my current every day device and would recommend either companies devices based on my usage. I currently use a Microsoft Surface Pro with Plugable USB 3.0 Docking Station if you care about these additional details. I have not tested this device with my MacBook yet.
Updating June 4 with additional usage comments.
Update June 10 with the device model numbers
Does the Sennheiser come with a name?