I use a Dex genie build (100dex, 50mag, rest in vit on a Discipline + the stat boost items). AD, Holy Path, Extreme Poison, Expel, ToP, Badge of Courage, Will Surge and Belief. If you go Demon on a veno, you don't need fortify on your genie because Demon Summer Sprint has a 6 second anti-stun effect and is up every minute. Sage venos have an easier time gaining chi + a longer stun/aoe purge/stronger amp but they lose out on the amp that Demon Nova gives. What I would say is for cultivation purposes, look up the skill effects and see which one your friend likes better. Both are good choices (although the majority of venomancers go demon).