RE: Getting into Fantasy Grounds
Fantasy Grounds is impressive and it's definitely worth the money. It's especially great if there is a character sheet for the game you play. Often you can upload your character file from a character generator and can start to play. If you are "only a user" - be it GM or player - it's lovely.
But the connection thing... First the GM has to host - you can't host for another person like other virtual game tables offer. And then FG needs IPv4 which is a real problem in Germany where a lot of people have IPv6 and you probably have to pay for the "business solution" with IPv4...
You can tweak and program a lot of things though it's not as easy as with Roll20 and the map making + using function of Roll20 is a dream. But I prefer Maptool to both of them ;)
I'm mostly just using Fantasy Grounds for D&D, so that's one of the places where it really shines. I haven't tried other stuff on it, but the 5e experience is really sleek, especially compared to Roll20's.
Connectivity is the one thing that's a pain about Fantasy Grounds. I had to reset my router to get port forwarding set up to get Fantasy Grounds to work (didn't write down the admin password, yay!). Fortunately, I have an IPv4 address, which helps. Do you know if the IPv4 requirement is current and/or how it interacts with the Alias system?
I think Roll20 might slightly edge out on maps a bit, but I use third-party stuff for maps anyway. I've used Maptool and don't dislike it, but there's something about Java apps that I really don't care for.