Hm... I rather think Slaanesh's "pleasure & ecstasy" zone looks like the one from Hellraiser series, where only ones having pleasure are Daemons. "Oh what sights we have to show you..." :P
I'd side with Khorne... at least he's promises aren't ambiguous, it's only "Kill kill kill kill", and whats wrong with a little frenzy and blood lust... I kinda think it would be like when I played rugby, just on 10th degree.
Cheers, Miljan