I've seen both of the movies and can safely say I don't care for them. The Titan sequences are great and the soundtrack is really good, but little else worked. The root of the problem is that few of the characters act like real people: they range from stilted weirdos and nobodies to melodramatic irritants. Even if/when they acted these ways in the anime, they benefited from time spent on characterization and character development. Also, the anime conveyed a real sense of tension and dread, which could explain and smooth over some of their eccentricities. Tension and dread are largely missing from the films, though, so the characters seem weird for the sake of being weird. And in the films' limited run times, they stay one-dimensional. Sure, we spend plenty of time watching them, but not on them -- it's the difference between observing someone and getting to know them. Eren, Armin, Shikishima, and the rest of the cast are not even fun to observe.
That was really my main complaint. The pacing can test one's patience at times, although this, too, goes back to the characters. Some people mentioned the colour palette earlier, and yes, for the most part, it is far too grey to look appealing. It comes off as a cheap way to create dread and atmosphere, without having to write a script (or film and edit a movie) that does so. The movies diverge from the source material, but the discrepancies didn't bother me much in the end.
One thing I will say: I thought the English dub made the first movie more bearable. I haven't watched the second one with the dub yet -- maybe one day, if I feel bored.
"Available for your home in 1995, only on Nintendo Ultra 64!"