I always recommend a mic. The pace of the game changes significantly when everybody talks. Remember that for a lot of players, Roll20 is just another casual game. That means they can be on youtube or facebook in between their turns. It's unfortunate, but true. Talking on a mic keeps more people enganged most of the time. It's a good thing. If your past experience is play-by-post, then texting is a huge step up. Well, voice is kind of like that compared to text. Everything just moves a bit faster, and feels closer to how regular, in-person games play. Again, it's more engaging for everyone, and leaves less room for distractions. I consider it a good thing. I actually don't want video on at all. I would rather have the bandwidth for everyone to have good audio. So, if you think your games feel slow, or players are getting distracted on their turn (and constantly having to be reminded what is going on), I think you'll start to weigh the advantages of voice more seriously. I know I have. P.S. I've never required voice for any of my games, but I always recommend it.