Burn Drive is just awesome. Very well-balanced and takes forethought and skill to use.
Since you can fire during Burn Drive, it's great for chasing down Hounds or engaging point-cappers early game. But, since you can't steer while firing it and most ships that have it handle like a cow in a shopping cart, you have to be very careful where you point.
It's very satisfying with an Enforcer due to all the turreted mounts making playing catch-up trivial, and I've even tried running a version with HMGs that works reasonably well to get in their face. The Dominator is less easy-to-use due to the fixed hardpoints, but I imagine the Onslaught will be great fun. Also, giving it to the Tarsus makes the "Wolf Pack" mission much harder!
-The Skimmer is great too, although the AI is way better at it than I am since they can skip around all over the place and still keep hardpointed beams pointing at enemy targets. They even use it to avoid collisions.
-The Omen's EMP burst is VERY powerful, especially against minimally-shielded ships. One Omen does a big number on large groups of fighters and missiles now.
-I haven't figured out phase ships yet. Great mechanic, but tough to use effectively due to the limited time you have to spend phased. It'll probably take some learning to do.
-Fast Missile Racks is great for sending another round of Harpoons into a venting/overloaded ship. Works great. The rapid reload on the Hammerhead is nice too with lower-flux weapons, although you can overload yourself pretty quick if you're not careful. Maneuvering Jets is nice, especially on an asymmetrical Conquest, but the Eagle and Falcon are still a little... uninteresting to fly, for lack of a better term.
-The Buffalo Panic is actually pretty scary if you don't have flak!