The differences between the Kore and Tana are still obscure. Certainly the ship compare notes are wrong, since they're saying the Kore can haul 30 and looking at the compartment shows the storage will never be the size of a Cutlass. The Tana comes with an upgraded reactor, a larger shield, internal 2X S1X5 missiles, and the wing tip turret is changed from utility (tractor) to weapons. It also comes with twice as many fixed mount weapons on the wing, but they both have the same number of mounting points so you can add 2 to the Kore if you like.
10 units is not much cargo. A Hornet 7C can carry more. If you want a cargo ship I would not recommend anything that small. The Cutlass is really the smallest cargo ship, and if you want to actually earn a living moving stuff, I suggest avoid anything smaller than a Freelancer.
The big question in my mind with the Tana is, how easily can you convert cargo space to equipment space? If you can install an EMP, enhanced sensor array and Void armor into the Tana, that little ship can be a real menace, especially working as part of a team.
Also just to note about the variable geometry, we don't really know until we can fly the thing, but the fact that the engines can lift the bird off vertically while it is balanced would suggest you can fly this way in space, which has the effect that the cockpit and weapons are all turned 90* from the main thrust. Anyone familiar with combat mechanics in things like Mechwarrior knows that this can be used for "orbiting" a target, which is probably the most effective short range brawler tactic.
Orbiting is basically to circle an opponent at maximum speed and minimum distance with your weapons trained on him. What this does is make you as a target move in and out of any weapon's horizon or available firing area in minimum time, so it is hard to even get a bead on your ship or Mech. It's of no use to do this in most fighters because without the ability to target at 90* from your flight path you can't shoot your opponent. To orbit with a fighter you need to have a turret, or in the case of the Reliant, actually turn the bulk of your ship to face target so you can use all of your fixed weapons (and everything else as well.) This makes maximum use of the minimum mount, and could enable the tiny Tana to take down large ships with very powerful turrets, like the Starfarer and Retaliator, without ever taking a hit.
And this is just one of the tactical possibilities opened up by the specific variable geometry of the Reliant. There are others. Definitely a ship worth learning about and flying, IIMHO.