I would like to say this first, if you are ready to tell me that I'm bashing on DC and Batman, I suggest you stop reading and don't even comment. Cause that's NOT what this is. It's pure opinion. If you can't accept it, it's not my problem. That being said, if you're still reading. I love The Dark Knight as much as the next guy but, I feel a lot of the love for The Dark Knight and the sole reason it's considered the best is because of Heath Ledger. Think about it, would the movie have been as good if anyone else was in the role? Of course not. X-Men has been pretty mixed among the fans of the comicbooks. I haven't read many but, I don't think the movies are bad. I think it just stems from the fact that they aren't the fans' X-Men movies. X-Men and X2: X-Men United are great CBM's and among the best. The franchise gets a lot of flack for The Last Stand and X-Men Origins: Wolverine. Why should a franchise of five released films catch flack for two bad movies (which I found them to be enjoyable for what they are). Continuity ignored, I'm looking at these two as single films. Here are a couple reasons why I feel X-Men: First Class is better than The Dark Knight.
Better all around Story

The story for The Dark Knight was good. But, the biggest problem I have with it is the plot hole where they never explained the whole Jim Gordon death scenario. Honestly, I'm not one to pick up on plot holes easily. I'm watching First Class as we speak and I'm not seeing any plot holes. Unless you count continuity issues as plot holes. But, I'm not counting continuity in this case as stated before. I found the premise and overall story for First Class more interesting and more engaging. Taking place during the Cuban Missile Crisis where Charles Xavier and Erik Lenshier put together a team to stop an all out war between mutants and humans due to Sebastian Shaw. It had good character development and drama while also having exciting action scenes. The intensity of the movie is really the best part of it if you ask me. Outside of one other thing, which I am about to get to.
Acting
Better overall acting. Much more convincing acting, that's just my opinion. James McAvoy did feel weak at times but that's it. Think of it this way, Michael Fassbender practically got universal acclaim for his role as Erik Lenshier/Magento. He's the Heath Ledger of that movie. Outside of a couple moments from James McAvoy, there isn't a single bad acting moment. Hell, Hugh Jackman's cameo as Wolverine was a bright but very small acting moment, despite being a cameo. The Dark Knight had Maggie Gyllenhaal. That was the worst casting decision Christopher Nolan has made outside of Marion Cotillard. Alright, I have to admit. I came off like I was bashing. I apologize for that. Outside of Heath Ledger, I just wasn't overall impressed with the acting in The Dark Knight. Lucas Till was another stand out in X-Men: First Class for me, as well as Nicholas Hoult. Also, Kevin Bacon. 'Nuff said.
It feels real
Bear with me here. I don't mean it's a realistic take where "if this were to happen, this is how we think it would happen". I'm talking that the characters, situations and struggles all feel real. Honestly, I feel no comicbook movie had really succeeded like that. X-Men: First Class was fun and exciting while feeling very real and very intense. The other X-Men movies, particularly the first two felt like comicbook movies which worked fabulous (the first two are of course). First Class had the fun of a comicbook movie but as I've stated numerous times, it felt very real. Characters felt like they actually existed. Obviously not everyone feels the same and that's okay.
Overall: The Dark Knight is a excellent movie and one of the best. There is no denying it. No matter how faithful to your favorite company you are, there is no denying it. X-Men: First Class works for me as being best only to The Avengers topping it. Now, it's not that high on my favorites, although at times I change them up. First Class tops The Dark Knight as (in my opinion, respectfully) not just a comicbook movie but, a movie in general. More interesting story with the help the VERY convincing acting and because of that acting, it all comes full circle and feels very real. Not a single dull moment in my opinion.
Yes, I'm expecting to catch tons of flack for this opinion. But, it's an opinion. Nothing biased here. I know I'm probably contradicting myself but, I feel that despite how much I love, The Dark Knight. I feel it's also overrated. First Class is a brilliant to start of a trilogy that has potential (as with everything else) to be the best comicbook trilogy. The only trilogy close to the best is, The Dark Knight trilogy. Days of Future Past is only going to be fixing some problems, not all of them as Bryan Singer has stated (personally, Cyclops is my favorite X-Man, always has been. I hope they find a way to bring him back). What do you think? As always, comment below and be respectful and civil when you do.