Stability. I have used a myriad of different systems for conferencing and virtual communication and none have been as stable as FUZE. Rarely get dropped from calls, at most I get a reduction in performance that then prompts me to actions that may alleviate the issue; ie. turn off my own video or turn off another users. While interruptions like this may seem bad, its much better than just being up and dropped from a call out of nowhere. Screen sharing, conference recording, and the interface itself are all nice in general.
I don't like the inability to easily transfer ownership of one room to another person. We often use persistent rooms to have a same location and in order to change the owner it usually just results in us creating a new room and having to send out a communication on that change. A small issue in reality. Playback on recordings sometimes compresses the video down to where its not very useable anymore.
We have a very global team and company, with coworkers spread out around the world. We need to regularly "meet" virtually to discuss various ongoing issues of the day/week. For those whom cannot attend due to scheduling, the ability to record and disseminate the information in the way is very useful.