Awesome
This film is not just a superhero movie, it is a beautiful classic film. The problem with what Marvel has done is they just throw a bunch of movies at you and hope you show up to the next one. This film not only tells a great story from start to finish it still sets up for more films.
Do not be intimidated by the 4hr run time. As others have said, it does not play like 4hrs and more of a 2 1/2 hour film that grips you throughout. It plays slower at the beginning to establish character background but Snyder does an excellent job of balancing that with action to keep you engaged. I have watched it 3 times in its entirety and all 3 times have wanted more by the end!
I will be honest, I am a DC fan (Superman more specifically) but even I have enjoyed what Marvel has done and Endgame was spectacular but I can honestly say that this film is better than not only all the other DCEU movies but Avengers & Avengers: Age of Ultron too. There is no telling where this universe would be right now if WB wasn't trying to copy Marvel and just let Zack film his vision from Man Of Steel to BVS to this and beyond, he clearly had an entire 5 film vision and you need to watch all of them to fully appreciate his arc. And if this was released as it should have been back in 2017 we may not be talking about Endgame now. Hopefully WB has learned from this and is ready to let Snyder finish his trilogy.