For those that have seen alot of Marvel movies:

It's not so much that I'm comparing the two in terms of what they've done, but the kind of villains they are. Thanos kills billions of people with the gauntlet, yet DC-Fan doesn't think he's a real villain because of his tragic motives (including killing Gamora). In a nutshell, Darth Vader is a perfect example of a tragic villain who doesn't necessarily enjoy or want to do what he does since he was manipulated in the first place into joining the dark side.