I like roll20 as well and use it from time to time but I really like the FG application. It plays on tablets and a few other OS... which is nice. ALOT of fantasy support for D&D, but I mostly use it for sci-fi games, horror, and other games.
I have an ultimate license, so if you would like to give it a go for free, just let me know and I'll set up a table for you. Gurps, Savage worlds and others have been reskinned for gameplay but I have a few that aren't modded for the public like Traveller.