I bought one too, and have no rank with Empire. In fact never been in Empire space - and certainly never touched any slave cargo.
But what to do with it? It is very poor with regard to shield strength and agility, even maxed - surely no good for combat?
Forget about the in-game maneuverability rating, it is -extremely- misleading. Put the biggest A rated thrusters on it and she's a joy to fly - really fast (fastest without boost, on boost second only to the Cobra mk.III) and she actually turns pretty well.
Shields cost a fortune to max out at 7A, if you put a few boosters you get kinda decent shielding but frankly, Clipper's shielding is far from impressive.
Firepower is great, but hardpoint placement isn't good for fixed weapons.
Lots of internals of all sizes, giving you good options.
Overall, this ship can be very effective in combat in the right hands, while still able to carry a decent amount of cargo. A clipper pilot is, on top of that, able to decide when the fight is over and withdraw in most situations, without the opponent being able to do much about it. So, you get great speed, good maneuverability and firepower, at the cost of shield tankiness, inability to land at outposts and hardpoints not being great for fixed weapons. But everything has some kind of a tradeoff - overall it's a great ship, forget that maneuverability stat and try her out.
I personally used her quite effectively in RES's, combat zones and also doing missions in order to rank up. Due to the generous internal compartments she's good at most tasks that don't involve landing at outposts, since you can have some mission specific equipment in your loadout without making major compromises (such as an FSD interdictor, or whatever else you might need).
I haven't done any pirating, but due to it's speed, firepower, and cargo capacity it's also a popular pirate vessel. Frankly, I haven't found inability to land at outposts very relevant. If I need to go to an outpost I either jump in my Courier or get a temporary ship if my Courier's not at my current location. Not a big deal at all, I had to go to outposts more earlier in the game, I find I need them less and less as time goes by.