Wolverine for the majority. Gamora doesn't have healing factor feats that would suggest she is capable of fighting through being eviscerated or having a major organ pictured, and even though she is a green chick who lives in space and gives the majority of KMC a boner she doesn't have any skill feats to place her above Wolverine either.
Like I've said many a times uber skilled fighter have many examples of operating outside of the parameters of their attributes by virtue of their skill, Gamora has never done this. She stalemated Thanos once in a sparing match, big deal, a twelve year old Black Widow got the best of Wolverine once in a training season - is Natasha the best ever super MA now? If you are are going to make an outlandish claim that Gamora is the best in Universe, I don't think its too much to ask for some displays of this alleged skill. She's never fought anyone of any significant skill and won (Wolverine beat her already... and hes pretty much the only person of notable skill she has fought), and she's really never done anything outside the parameter of her attributes. She's an amazing fighter because she was trained by Thanos, and alternatively Thanos is an amazing fighter because he trained Gamora. Circular logic that makes no sense? You tell me.
Batman, Cap, and virtually all the street level MAs are peak humans or around there, who have on occasion beaten and damaged the most powerful and dangerous of enemies by virtue of their skill. They operate above and beyond the limits of their bodies. Gamora doesn't. Relative to her attributes I've never seen her do anything half as impressive as the things street level MA's do on a regular basis.
I think - for what ever reason - its just a popular opinion that if you are operating in space you are by default better than earth bound heroes... which is absurd. I mean, theres a reason that Gamora knew who Wolverine was and he didn't know her, because when your the best there is at what you do, lesser people are always looking to test themselves against you.
Play League of Legends for free and reference me - GentlemanZombie - when you join