Roughly half of our company uses UberConference with their own account. It allows employees to manage their own conferences and screenshare sessions. Meeting communication is improved because it is simple for people outside the company to join the meetings and share their own screen if necessary.
While GTM has more features for managing a conference, it is really geared towards larger meetings with someone who knows what they are doing on GTM to manage setup, muting, unmuting, chat, recording, etc. UberConference is really great for licensing for the end-user and going IT-free.
I think it works very well and is easy to manage. The experience is even better if you buy-in to Dialpad as your phone system (the softphone has UberConference built in, and licensing can be managed through the Dialpad admin portal). Adding more licenses is simple and quick too.