Me? Personally, I don't like the Superman franchise that much. I'm annoyed at how the citizens of Metropolis don't realize that Superman is Clark Kent without his glasses. Although I do give it props for having Lex Luthor, a villain with a lot of money who can do whatever he wants.
When it comes to Marvel's cosmic heroes, I really can't call any of them my favorites. Silver Surfer's cool when written well, I'm indifferent to Warlock and the Nova Corps.
Now, Thanos, on the other hand. A badass, cosmically-powerful, murderous psychopath...who is madly in love with the Grim Reaper. Everything he does is just to impress her.
I'd say most villian ARE more interesting because they usually have really tragic backgrounds.( For example: Magneto lived in the frickin' Haulocaust and afterwards still wasn't accepted cause he was a mutant.) most super villians or just regular villians don't just decide to be evil, they have a motive.
To be honest, for me a superhero story needs both a good hero and a good villain, and although I tend to like the heroes better and relate to them more there are still some awesome villains out there. The Joker is one of my all-time favourite characters, period. Enough said.
I prefer if the two characters, both hero and villain are equally interesting. Batman is an epic hero fitting enough to face off against a gallery of villains that are all cool and interesting in very different ways. That's why i love Batman and his enemies. they are all totally recreated, team up with another villain and provide an even more interesting story. No one knew how cruel the Riddler can be just to prove that he is smarter than Batman.
Also I love morally ambiguous characters. People who are both capable of altruism and atrocity. Like Simon Dark and Red Hood. On Marvel's side I find them all interesting and ambiguous, all heroes are fighting for the common good but on very different ways(Punisher/Namor/Iron Fist/Ghost Rider kills all their villains while Spiderman/most of the X-men/Squadron Supreme lets them live) unlike DC heroes who all prefer if the villain did not die and serve for his/her crimes.
Hmmm.... I guess I'm in the middle cause I like the bad guys from Batman but also like Batman (dark versions of him when he's questioning his sanity, etc.) I never really liked Superman because he seemed too perfect but Lex Luther is cool. I like Wonder Woman (From the Lynda Carter and in an animated movie.) but I don't like the villains. With X-Men I like some of the good and bad ones (especially Deadpool) I never really liked Spiderman, I don't know why but I don't, but I like the villains.