This is where it all started.
I have always been on the 'receiving side' of this product - Go To Meeting - and have attended many webinars that has used this platform.
I'd say, it's a de facto standard for online meeting - and almost all kind of training. Most trainers use this for promoting a message or product - goes without saying, most people know about this product - and like it, too.
At times if there is a heavy load on the server, some audio issues may crop up - and very rarely, I lost connection, too.
Overall, but for this, I would not have learned many things online.