Hydrazine is better IMO if you compensate the rotation with man fins, inertial damper, etc. Rushing does involve moving in a straight line down corridors. With PD you typically want to wait a few secs for your PD to attach so you have time to rotate yourself into position to rush. PD levi is about keeping your levi alive as along as possible while PD does the work, so defensive items like armor, reps, nrg, etc are most important. You don't need a speed mount.