I am not going to lie and say that they are good movies as a rule. Sure there may have been a gem or two in there, but otherwise they are a perfectly normal set of Summer/Winter blockbusters in my opinion. The average movie that hits my Theater I have absolutely zero interest in watching (and less in paying to watch), but the marvel films at least represent a certain level of professionalism (I am shying away from saying quality here) that prevents the movie from being obviously "bad" (outside of a few out layers like Iron Man 3). They are just there, they are familiar, and they give me a movie about some of my childhood heroes (though often with half of the story either wrong or mixed up, but that is just cinema in my experience) that has a ton of action and occasionally manages to tell an interesting or (more commonly) passable story.
Meanwhile I've seen 5 or 6 action films over the past 3 years that are just complete crap and maybe 1 or 2 that are actually "GOOD". I think that most of us has to face the fact that hollywood is just out of ideas and needs to mine products like marvel and DC comics for stories. Then rather than just leaving them alone at their core (I mean I know that the overall quality of a comic book story is crap in general, not to mention the reasoning they typically give), they try to rewrite them using other parts of the character's story and some parts that are completely unrelated, mix it all together and press out the shiniest turd we will get this year.