In my opinion, the exact opposite is true. I found the Marvel films immensely enjoyable, whereas XFC was one of the most disappointing comic book films ever. It squandered a great deal of its potential by screwing up the X franchise's timeline, the characterization was terrible, especially for female characters, and the action was as lame as always in Fox films. The only thing I enjoyed about it was Charles and Eric's relationship, but of course that followed upon what was established in the first three films.
Charles, unfortunately, came across as a very naive person who inadvertently betrayed his own race by giving the CIA too much information about mutantkind as well as the potential means to slaughter them all (Cerebro). He came across less like MLK and more like Uncle Tom, willing to do anything to appease humans up to and including stabbing his fellow mutants in the back. Yet he was willing to let the mass murdering Nazi psychopath Shaw live. When Erik killed Shaw he was thoroughly justified and Charles was just as thoroughly wrong.
The makeup jobs on Raven and Beast were atrocious and distracting. Raven's origin and personality were in complete contrast to the misanthropic loner she was portrayed as in the first three films. (How the hell did Charles convince/force his parents to "adopt" a naked, blue-skinned seven-year-old thief?) She was shown as a loving sister until the last few minutes of the movie, when she inexplicably decided to leave her critically wounded brother lying in the dust and run off with the man who crippled him. And this after merely speaking one-on-one with Erik a few times and making one of the worst seduction attempts ever. Raven's complete 180 degree turn was ridiculous in light of all that went before. How, exactly, she would eventually turn into the mostly-silent assassin she was in X 1-3 was left unexplained.
Shaw's ultimate plan to kill all the humans by causing a nuclear holocaust was pure stupidity. Even if we accept his assumption that he would survive, 99% of other mutants would not. The few who lived would have inherited a nuclear wasteland, with neither the food nor resources to support a mutant population of any size. That's why total nuclear war was referred to by the acronym MAD back in the day: Mutually Assured Destruction. Shaw was supposed to be some sort of genius mastermind so why couldn't he see that?
One other thing: Some of the acting was painfully bad. January Jones....well, what is there to say? Zoe Kravitz is lucky to have famous parents. Not that the script gave them much more to do than wear skimpy costumes and fail at being menacing. Rose McGowan was mediocre as Moira McTaggert, but the problem was that the character was inexplicably downgraded from a major player to an inept junior g-woman. The ultimate insult was having her mind wiped by Xavier at the end. Since Moira was shown utter disrespect all the way through I can't say that was surprising.
In short, X:FC was a mess of a movie and as such I wasn't surprised that it did so poorly at the domestic box office. A total haul of $146 million puts it in FF territory, which is a bad place to be. Fox got lucky with the overseas haul, otherwise they would be looking to reboot their non-reboot next year.