Roll20 is the VTT I use for my games. It has taken me a long time to get comfortable with it, and still don't use things like dynamic lighting (I don't find it adds, and takes a lot of mental bandwidth to utilize). Some game systems--D&D, Call of Cthulhu, Castles&Crusades, Dragonbane--have compendiums available (DCC will have one soon, although my good buddy Ed has the initial roll-out and doesn't love it), while others do not. D&D5e has the best tools and support: the game is effortless to set up and run using that system, which makes sense because it is the biggest game out there, has tons of players, and deep pockets. C&C, which I am apparently ever on the cusp of running, has some support, but it's not awesome. No drag and drop tokens, for example, which means I have to manually add monsters. No drag and drop equipment or weapons. Not the end of the world, but time consuming. So as I've been kicking around the idea of a West Marches OSR campaign, I've been struggling to figure out which system to use to do it.
Meanwhile, Foundry VTT is by many accounts much better, and Troll Lords Games--the maker of C&C--are putting their development energies there and not on Roll20. I don't know if I have the motivation to learn yet another VTT, but if that's where the good stuff is going to be, I might have to.
Unrelated news: I sold a bunch of RPG stuff I wasn't going to use anymore, and got $425 in store credit at Noble Knight Games! I think my lot was worth more than that, but whatever. This is one way I can support my FLGS, even though it isn't local for me (I think they are in Wisconsin or someplace like that). I am looking forward to spending that money!