Attack on Titan is better than My Hero Academia in terms of animation, story, and characters imo. Here's why I think:
1. The characters are written with a lot more depth and with a style that draws you to them. I despised Jean for a very long time, but I watched his development, watched as his character changed, and now like him a lot actually! Another thing is that it's very easy to sympathize feel a certain pull to almost every character, for example, Mikasa. Unless you're one of the people who absolutely despise her (honestly it's more of a very loud minority, but still), it's easy to sympathize with her and understand her behavior. She's lost almost everything but still continues to fight, which is why she's my favorite because god damn that girl just needs some love lol. In AoT I feel attached to a lot of different characters for a lot of different reasons, and with MHA the only characters I ever got attached too were Ochako and Deku, and I didn't really care for anyone else.
2. The animation. Both shows are what I'd consider to be very well animated, but I find AoT's visuals a lot more striking and vivid, especially in the third season. Minus the very rare background shot where a character's face looks a bit distorted, everything (and by everything I mean everything because holy shit I could never) is drawn with a lot of intricacy and skill. The fight seems are insanely pleasing to watch (and this is coming from someone who isn't really a big fan of those) and you can easily understand what's going on instead of it being a character moving everywhere, dust flying, lights flashing, all that jazz, and it's just realy nice. My favorite fight scene is probably Kenny vs Levi because omg the voice acting and animation was just chef's kiss. And this isn't to say that MHA doesn't have good animation, but in my opinion there's honestly a bit of a quality difference.
3. The story.
I can say that I enjoyed MHA's story while I was interested in the show (now all I really care for is Ochako and IzuOcha), but AoT's story kept me a lot more interested and on the edge of my seat. With MHA there were never any moments where I was like "Ooooooh, what's gonna happen next?" because you could already kind of tell. Even in the manga where it's supposed to be getting dark, they've only killed off two minor heroes and I highly highly doubt that unless it's someone like Satou or Koda they would kill anyone off from the main classes. I don't even think they would do that to Aizawa tbh. With AoT you aren't really ever sure what's going to happen next, or who's going to make it out of the next mission, and I honestly really admire the fact that they aren't afraid to dispose of characters. There are a few where it wouldn't really make too much sense to kill them, but even if they're loved by the fandom like Erwin or Sasha was, if they can be disposed of for good plot reasons then Isayama isn't afraid to drop em lol. With Erwin's death it was shocking, but it made sense and in turn didn't really anger anyone other than a few die hard Erwin stans, a lot of which actually understood the sacrifice.
Not to mention the plot is a lot more deep than MHA too. Attack on Titan has multiple plot twists, where unlike MHA are pretty unpredictable (minus the female titan which Idrt was supposed to be a huge secret in the first place), and it's realistic too. The plot twists shock you at first, but then you can go "Oh yeah, that makes sense" because there's a lot of build up and care that goes into the twists to make sure that there aren't any plot holes or that it wouldn't be pointless, which is awesome.
These aren't to say that your opinion is invalid for liking MHA more than AoT lmao. This is all my opinion and you're free to like whatever you want. If you think MHA is better than AoT, then great! Good for you! We have differing opinions, and that's completely fine. I wasn't here to try and change anyone's mind, I was just expressing and opinion that I hold strongly lol.
