As far as I'm concerned, the US KOC kicks major ass. No sticky keys, modded the TT, works like a charm. Been pounding away at anothers and flashing 7's and 8's ever since it came out. No problems whatsoever! Only thing was that my first Beatmania bundle came with a defective KOC, but i just had it replaced, and now it p-owns. lol.
For those who don' t like a stiff TT, mod it (believe me, the KOC design for the TT sucks [check the pics in the sticky concerning the plastic doughnuts if you don't know what i mean]). Actually, even if you like a stiff TT, please just mod it and tighten the screw accordingly. Trust me on this one. If you don't like having to depress the keys hard, mod them. Design it to your preference, cuz ultimately, you're the person who has to use and adjust to it.