Authorative, manipulative, and dangerous, unlike Walter White. Walter White is somewhat menacing and he is dangerous, but he does not compare to Frank Underwood. Who would you rather meet in a dark ally? I would rather meet Walter White. Frank Underwood may kill you or even have sex with you. Underwood is the better character, in my view.
No contest. Walter White is a much more well-rounded character who we see "grow" (in a dark sort of way) and change in realistic ways through the show. FU is just flatly evil with a polished politician's veneer.
Walter was Real, whether it was just one facet, still sorta doesn't make complete sense. Though Underwood is a snake. Walter is more of a Badger, they'll stand up to you and won't give up unless they're dead. (Maybe I'm wrong.)
Walter White is the better character because of his progression. Frank Underwood has remained the same over two seasons, while Walter White went from mild mannered chemistry teacher to maniacal drug dealer.
While kevin spacys character might be great, you cant compare anyone to the best of all time