Giving it to Bats. If mostly because of Cap's three films, Winter Soldier is the only one of the three to me that feels like a great film first and a great comic book film second, while First Avenger and definitely Civil War feel like great comic book films. Now there's nothing wrong with that, even though Civil War is part Cap/part Avengers films, but of the three, Winter Soldier is only one I would revisit.
With Batman, conversely, at least more so with Begins and Dark Knight, they feel more like crime dramas first and the protagonist happens to be Batman. That often helps the replay value of these comic films when they transcend their genre, like Winter Soldier, Begins, and more recently with Logan. I ultimately lean more towards Batman primarily because Batman Begins is still my favorite comic film period and is a great character study on top of being a solid comic book film.