Dragonking or cloudhammer

There's really no substantial differences in the fittings. They're basically all made in the same factory in China of "mystery metal" and painted. That includes both tsuba, even the one that looks "iron." Synthetic samegawa (rayskin) is actually considered superior to cheap real rayskin, so the difference is probably insignificant. Personally I prefer brass fittings, because at least you know what you're getting, and they can be antiqued to look reasonably authentic. It's not uncommon to get big casting bubbles in them, but at the price you can't complain. Leather doesn't really need hishigami, it just behaves differently than cotton, silk, or whatever they make the synthetic silk out of (usually polyester or nylon I would think).

So as suggested, the most important difference between the two is the blade. Differentially hardened is still fine for cutting, but you run a higher risk of warping the blade on a bad cut, after which it needs to be straightened. Do that enough, and it will break. So for beginner cutters, through hardened is recommended. Both would be decent cutters though.