Which route is better, love or corruption?
hmm really hard to say. if you're more into love stories and whatever 'wholesome' scenery, you may tend to like the loke routes more appealing.
if you're into completely utterly destroying some girl, bottom out, unspeakable things beyond any horror movie, you're out of luck, there's nothing of that sort of extremism in the slave route.
but the slave route gives different content (not so much in bk1) and different stories, and sometimes it's just tempting to be the 'mean guy' who always checks 'what's in it for
me?' first and won't give a dead rat's ass about anyone else.
i'm completionist and thus have to play every facette of a game anyway.. it's a curse sometimes, but by now a developed habit to 'go the other path, too' which in this case turned out to be good. i wouldn't want to have missed out either route.