Kender are annoying kleptomaniacs. Warforged are cool to at least some people. I say the warforged wins.
Now, I've witnessed one fight between a warforged fighter and a rogue, but it wasn't a fair fight (the rogue was possessed and not build properly). The rogue attempted to sneak attack the warforged but failed (she hit but the 25% fortification was real handy); I was controlling the warforged and did not retaliate with non-lethal force. Flop!