Simply amazing!
The Nativity Facade, the original work by Gaudi, is simply amazing. The beauty and complexity of it is staggering.
The Passion Facade, newly completely, is much more modern and contemporary. It is also very moving.
Do pay the extra EUR 2 to get up the elevator to the top of the tower, and get a view of the city.
They are doing work to finish the museum. A large part of it is new, and you can see that some of the old cathedral actually was not well maintained, and there is a lot of graffiti on it. What a shame!
I suggest buying a package ticket for an extra EUR 1 which gives you access to Gaudi's house inside Park Guell.