I played several sessions in Fantasy Grounds 2 and enjoyed that, though it seemed over complicated software wise compared to Roll20, it had advantages like having a lot of the stats and libraries built straight in (though it could be tricky to set it up to work).
Roll20 seems a lot more basic, but solid and does everything you need. Definitely a good way to play if you can't get together face to face. Hell, I do play face to face and sometimes think about playing on Roll20 just to play a system I like more than what we do in RL.