I think Warner Bros can be stupid and stuborn. But at the same time, when the filmmakers have a good chemistry with them, then there's magic. For example, look at the relationship between them and Chris Nolan, Martin Scorsese, and Clint Eastwood.
And it looks like Zach Synder and even the likes of McG are cool with WB. So when they want to be, Warner Bros can be kickass.
However, Fox is the complete opposite. They only have working relationships with James Cameron and..Laz Burrman. I'm not discrediting them, but that's it (and they make a movie every 10 years or so).
Fox tends to be cheap, hire cheap unproven directors, and looks out for the bottom dollar instead of quality.