My issue with Slaver Weapon is that it's just a puzzle-box, and our heroes do very little to solve the problem. Chuft Captain fucks with Powers He Does Not Understand and blows himself up. Had out heroes been more active in solving the problem (say, tricking the Kzinti into doing themselves in), I'd have given this the nod over Albatross, but the lack of meaningful action on the part of the heroes lowers my estimation of the story, cool as the concept is. So Albatross gets my vote.
I always imagine Slaver Weapon would have made a great TOS episode with our guys vs. the Romulans fighting over the weapon that could change the balance of power.