Mustang variants are free to try for anyone with current alpha access.
The ship dynamics in this game are much more involved than in Elite imho. When SC said they were going to model every maneuver thruster, its power and swivel speed & directional limits, I thought it was marketing BS. But they actually followed through.
For instance the Mustang doesn't have side-pointing thrusters, it uses differential thrusting with the forward & rear thrusters to yaw your ship around. It has weak downward-pointing thrusters and very strong upward thrusters.
So if you're flying towards an asteroid and just yaw to point the Mustang to one side, your crosshair will point to the side but you'll still be flying towards the asteroid.
(There's a flight path HUD marker similar to contemporary western jets).
So you have to roll the ship around so the down- or upward (ideally the latter) thrusters can get to work, or flip the ship around to use your main thrusters.
The 300i on the other hand has side thrusters, but the maneuver thrusters are much weaker than the main thrusters, so you may still want to flip the ship around and make the main thrusters push you in your desired direction.
The flight control system is deliberately imperfect and in the Mustang you really notice your thrusters kicking the ship around when trying to stabilize it on your desired flight path.
SC still has artificially low ship speeds (way lower than speeds in I-War), but this is to avoid multiplayer lag madness.
Interestingly, ED and SC devs have quoted 500m/s as the maximum in-game speed you can have with today's technology and network infrastructure.