I got this game cheap so I tried it, cause I always enjoy playing a challenging beat'em. I have mixed feelings about KoF XIII.
I played this quite a while, mostly online to find worthy challengers. What I found most of the time instead where veterans, who played this game hundreds or even thousands of hours and others who play with dirty tricks, repeat unfair moves over and over or trapping you in the corner an starting an endless combo.
While I think of me to have a settled character, I never felt a rage like this before. First I have to wait an enormous time to find another player, then you are confronted with a lv.40+ pro who eats you for breakfast. The most annoying part is you can't even refuse to fight unless you quit the game. There is no button to return to the main menu, once the game puts you together with another player!
The reason I kept playing is that once in a while you meet a guy who is about the same level as you or slightly above. Your heart is racing, you are glued to the screen. You analyse his movement, learn and beat him in the last second. That is the moment where you get the most out of it. And I am not even mad when I lose in a fair duel like this.
Should I judge the game for its player base? I don't think so, but I am mad at them for a slow servers, bad ui decisions and bad player matching mechanics. At its core it is a solid 2D-fighter with nice graphics, which doesn't let me enjoy it like I want it to.