Mono or stereo: which Jabra headset style fits open-plan offices?

The answer here depends on your own use case. With a monaural headset, you always keep one ear open, and this is helpful when you need to respond promptly to your colleagues whilst remaining alert in the online call, meeting or conference room. With Binaural (Stereo) headsets, you will have the benefit of being able to concentrate more on a call and exclude the background noise and chatter.