I think I am one of the few who is in the middle on this movie. I didn't love it and didn't hate it. It has some obvious strengths - acting is outstanding, loved the cinematography, the attention to detail. But I thought the film displayed Nolan's weaknesses as a film maker - namely, his lack of trust in his audience and his desperate need for an editor.
Respectfully, I think the comparison to Lincoln is crazy. Oppenheimer would be 1000x better if it tried to be like Lincoln (or, for that matter, Sorkin's Steve Jobs script). Biopics are usually bad films because they try to take on too much, so end up being a mile wide and an inch deep. Lincoln was focused on the final 4 months of Lincoln's life and the passage of the 13th Amendment. Steve Jobs focuses on three press conferences he gave over the span of 14 years. The first 2/3 of Oppenheimer is a technically well made, big budget, paint by numbers biopic, with all the usual trappings (and a needlessly distracting, ever present, score). It starts with Oppenheimer in grad school (1926ish) and goes through 1954. The lack of focus meant too many characters with too little depth - no exploration, just endless exposition. By the end of the film you don't really get a sense of Oppenheimer, the man. It was like reading a wikipedia article, but with better special effects.
If Oppenheimer was structured like Lincoln, it would have focused on the security clearance hearing, and made callbacks to his communist ties and manhattan project efforts. That movie would be much better, IMO.
I left the theater really wishing Oppenheimer could have been made in a similar way as Chernobyl, as a 5 part high budget HBO limited series. There are some parallels between the stories (nuclear power and its devastating effects, the scientist/government team up - Oppenheimer/Groves and Legasov/Shcherbina). Chernobyl had the space to really tell the story. Oppenheimer, the film, did not.