A friend of mine ran a campaign 4-5 years ago on this. We had all played P&P in high school but never had time to get together anymore, so we had been researching an online way to do so. At the time, this was the best 'online tabletop' offering we could find, and I am really surprised that a larger company has not stepped in with a slicker offering.
I haven't used FG since, but mainly because we petered out on P&P interest. FG got the job done, we successfully ran a 2 year campaign over it with 4 people. However, my overall recollection was that it was very clumsy to use. We had constant issues with connections and update incompatibilities. There was a lot of fidgety stuff that is impossible to describe now. It was also quite slow and frequently lagged or even booted people. I would hope that most of these issues would be fixed by now, but I recall in the two years that we played it, that updates were slow in coming and often made things worse as often as better. Admittedly, a big part of the problem was that our DM often modified things 'under the hood' in FG, and that led to many of these compatibility issues. FG is /very/ moddable, if you know what you are doing. And irritations aside: we managed a campaign on it. Face to face P&P is not without it's own host of headaches, after all. I just felt that there was a lot of room for improvement in FantasyGrounds even if it was serviceable.
I seem to recall they offer (or used to) a demo version - highly recommend you try that first with a short campaign. Check their forums for open campaigns that you can join. This many years later, it is hopefully more polished than I remember!
Good luck!