Batman is an interesting character... no doubt. But he can't support an entire universe of movies alone. (I mean he can't exactly carry the proposed Suicide Squad movie can he? He's not likely even going to be in it.)
In the past, DC movies have not faired so well due to the fact they try to be too grim, gritty and dark. Especially in cases when they don't need to be so dark. I mean Superman isn't really a darker character, it doesn't suit him. He's supposed to be the pinnacle of justice and a shining beacon of hope. Metropolis is supposed to be vibrant, full of life and colour. Not washed out and solemn (like Gotham).
Which is something that I like about Marvel's movies. Take a look at any of them and you can still feel, that while there is a threat to the characters, they also can have fun and show that things won't be so bad. The moments of upbeat and comic relief in them help to balance the audience out some so it's not just ultra serious all the time. And given that comic book characters are supposed to be bright and colourful... it makes sense.
So if I haven't really made my stance clear... I'm leaning Marvel here. Thus far I feel that Marvel's movies have been solid and fun movies while DC's haven't really been that great. I've gone back and rewatched some (all 3 Iron Man, both Thor, Avengers and Cap 1) of Marvel's movies multiple times because they're fun and good movies. But I can't say the same of DC. (Aside from Nolan's Batman trilogy.)
I'm excited to see what they do for basically all the movies they've announced (except for Ant-man, whom I don't really care for as a character).