A while back I left Roll20 for a number of reasons, and I've picked up Fantasy Grounds as an alternative. I chose it because it's relatively well-known and a lot of people swear by it, and it has a nice ultimate package that allows anyone to join you without having to worry about their own subscription or the like.
It's also more "feature-complete" than Roll20 in terms of how it works as a tabletop simulator, though I haven't had a whole lot of time to spend on it yet.
That's something of a weird thing to say, because I know that in theory Roll20 does almost everything that Fantasy Grounds does, but it does it in a way that requires more intervention.
For reference, you can totally use Roll20 to fill out a character sheet and use macros (assuming that someone has made a character sheet–the same limitation applies to Fantasy Grounds), but on Fantasy Grounds you're able to drag class, race, and background options into a character sheet in 5e and have it "just work", though character creation isn't really built into Fantasy Grounds like it is on D&D Beyond: if you make a mistake it won't fix it for you in any way.
A rather sloppy combat test.
What really sells Fantasy Grounds for me is that it provides really slick high-quality features. It's not intuitive–I'd describe the interface as being sort of an apotheosis of late-90's UI design–but once you figure it out almost everything flows so quickly and simply that it's not at all difficult to use. Generally things drag and drop into place or are interacted with using a right-click context menu, and once you figure out that everything else comes together. It really feels a lot like the UI of Troika's Temple of Elemental Evil game, and is similarly complex until you get used to it.
I'm going to post more of a review on the weekend, once I've (hopefully) run my first game with it.
The one potential downside is that since it uses a host-client connection, you're more likely to have problems with connecting through to other players than you are on Roll20.
