Titan grenades are point control/disruption types rather than pure damage, but you'll find that in games like control which force people into points that point denial is very useful. Also the range of the super is based on you because unlike the others both the defender and the striker both have close range supers. A fist of havoc will leap you forward quite a bit but it still focuses around you. Point control comes up again if you use the aftermath ability, allowing you to still kill anyone who runs in to try and get a kill on you with your back turned. You won't feel as fast as the other classes but once you get lift going in a horizontal direction you can feel slightly faster. Be prepared to be a big target in pvp. For pve you're going to feel like a badass destroying those who'd dare touch your fireteam. Can't tell you much about defender since the only people who played that subclass are bungie people.