I don't mind going in blind, but I'll watch one of Mizztek's (MTQcapture on Youtube) videos as they're short, sweet, to the point and loaded with puns. She will even point out when she messes up (that Titan HM blooper video was hilarious). But I use these videos to give me an idea of what to expect from the dungeon and boss encounters. Nothing truly beats personal experience (and practice!) to figure out what's personally best for you.

I find Mr Happy's videos to be a tad on the boring side.