While I'm disappointed in the running time... I'll still see it in the theater. I mean, really... I want to see the FF on the big screen... and that outweighs my feelings about the how long the movie is.
There are plenty of reasons that I was unhappy with the first film, but there were reasons I enjoyed it too. I expect that I'll have the same feelings with this one.
In the end, I've come to realize that the movie FF is NOT the comic FF - and shouldn't even be expected to be. As long as Fox owns the property for the movies, it will be this way.
I can either enjoy what's being released for what it is... or I resign myself to never, ever seeing the FF in any form on the big-screen in my lifetime. I'm not sure how long Fox's hold on the FF license will last... and I can guarantee that it would be another decade or two before Marvel or another production company would consider releasing a remake once Fox's license lapses.
So... knowing I may never see a truly faithful adaptation of my favorite heroes on the big screen in my lifetime... I'm not going to let something as small as running time spoil my theater experience.