Uh, Kumho's are Korean, not Japanese.
I haven't had any personal experience with Falkens, although they're pretty much a cheaper tire made to compete with the likes of Nitto and such (Which are AWFUL). Also haven't really heard too much about them either. I might try a set just to burn off on autocross and time trials...
I happen to dissagree with the "general" opinion. The vast majority of American tires below 200 dollars a piece are absolute crap. Continental? Goodyear? Bleeeeech. Absolute ASS on track, even with my POS 1990 GS.
If you want confidence that you're getting an EXCELLENT price/performance, go with some nice Yokohama AVS Sports if you want a nice tire in the sub 200 dollar a piece range. If you want to go a little cheaper, go for Dunlop. Both of those have a very good reputation.