Beautiful, tense, and spare. I've been interested in how Nolan's last few movies have had extended action sequences fill out their entire final acts, and here he takes that even further: the whole thing is basically one sustained note. As in his other recent movies, a lot of the tension is maintained with the encompassing, propulsive sound design and score, but here he fits in more striking, emotive imagery, particularly the foam and wind of the desolate beach. And the movie definitely benefits from having trimmed down dialogue, avoiding Nolan's typical weakness; it gives the whole thing a touch of stereotypical British stoicism.
I disagree with those who think it doesn't evoke enough desperation. I thought it did that very effectively, in a nicely restrained way. It let the scenes and characters' actions bring emotion into the story naturally. And the arrival of the flotilla was rousing as hell. Though I do agree with Trans' criticism that the beach segments seemed like a day and a half instead of a week.
Nolan ranked:
1. Dunkirk
2. Interstellar
3. The Dark Knight Rises
4. Inception
5. Insomnia
6. The Dark Knight
7. The Prestige
8. Memento
9. Following
10. Batman Begins
I wouldn't call any of them favorites, but the bottom two are the only ones I dislike. Though I don't remember Insomnia, The Prestige, or Following very well.