All odd numbered Star Trek films are under-rated.
Some are pretty bad but none of them are as bad as they are made out to be.
Quantum of Solace is exactly as bad/good as Casino Royale Sans Cheese and Skyfall.
Batman Begins and Dark Knight Rises are as good/bad as each other.
Superman Returns is a much better film than Man of Steel.
Alien 3,4 and the first AVP movie are under-rated though far from perfect.
Back to the Future Part 2 tends to get bitched about for being dark and confusing when if anything it could do with being more convoluted and the usually loved part 3 is a bit of a let down from my perspective.
X-Men 3 detractors tend to forget how dumb and badly scripted the first film was.