So I've been playing since the very beginning and I've always went with the purity route for the challenge but what do you guys do? Pure, Mix, or full corruption?  

Ironically (because I definitely originally bought this just for the nsfw) Nightmare Pure (or nearly pure) runs are my favorite. Balancing the economy and racing the clock before her mind breaks is a lot of fun, and I enjoyed the thrill of trying to one-up my new game+ score each time. I've tried doing a corruption run recently and it honestly just feels kinda slow after how hard I've gotten accustomed to pushing Aura, tbh.

I say nearly because lately I always take 2, sometimes 3 lewd acts-- I read the initial book for +3 atk, get the discount from the alchemist, and sometimes held the formula peddler. Having the momentum to beat my earlier scores simply got very hard without those once I'd started pushing into the very late game.  Now that my victory score is almost maxed out save the -6 points from those 3 acts, though, I'll probably do my next run completely pure again.