I'm a huge fan of both of them! Marvel and DC, as someone mentioned before - how da hell you can like one, but not other? Unless that's a clear sign of extremism or someone might be ultra huge fanboy of a single hero, but then, don't he/she dare to call themselves "Fans" of Marvel or DC.
The only thing, which has 2 sides of a coin is the whole multiuniverse thing.. The moment you get into it, you can't even feel when you go all the way to 1950s or even beyond just to fully figure it out. Although I can say that storylines are amazing, the arcs are superb.
Movies is one thing, I am very happy that I was born in a perfect age and grew up on these cartoons & comics and I can enjoy them being released slowly.
Speaking about TV series - there is a lot of questions, cringy cliche's and stuff, but they do make them enjoyable, so that's the best part of it.