Hi Adam,
according to your profile, you seem to be responsible for some kind of web conferencing solution, so your question here appears to be loaded.
I use BigBlueButton for teaching and online meetings and find it exemplary. I use appear.in for ad hoc meetings and quick chats with students. I also use Google Hangouts and occasionally Skype for the same purpose. I've had very few problems with either. In particular appear.in (which requires no registration) and Hangouts (which most people are already registered for) are particularly attractive.
If you need more information to improve your product, I'm available for hire and can provide detailed reports on user experience from both the teaching side and the learner side. if you want to tell us about your product, then I'm sure that those who are interested can check it out for themselves via your profile.
All the best,
Andy