I had an adder, fine upgrade to the hauler - a lot more capable should you need to defend yourself.
My problem with it was that I had a mining laser and a burst laser on the small hardpoints, and a pulse laser on the medium one. Admittedly, she was not really built for out and out combat, but if attacked - whilst I could see off Eagles and even Cobra's, they would outrun me and jump out before I could finish them, so no bounties - but kept me alive.
Now flying a MkIII and loving it so far, but perhaps traded in a couple of trips too early and left myself short of funds for any upgrades (and indeed any decent cargo) so working the balance up again so I can upgrade at least the FSD and hardpoints.