Del Toro's Frankenstein was visually insane. I got the chance to see it at my local theatre in 35mm and half the time I couldn't blink. The sets!! The costumes!!!! The acting???????? I wish I could be more eloquent about this particular aspect, it was truly a visual feast.
To address the elephant in the room: It IS very different from the book, and if you're familiar with his work, very Del Toro-esque. I agree that the themes of the book got watered down and a lot of the grey area exchanged for a very clear evil vs. innocence/goodness binary, a not-so-subtle mirror held out to the audience that some may find heavy-handed, but I didn't go into this film thinking it would be a one-to-one adaptation and I feel that saved my experience of it. I do think that despite the changes there is an underlying respect for Shelley's novel, but a very clear thematic shift. Still, it does capture the bitter-sweetness and painful existentialism of the original story for me, even if it is less queer and very much sifted through the lens of a monster-lover male director.
Spoilers: I did find the ending bit a little bit messy after some reflection. But overall, it feels to me that the focus of the film is a great empathetic take on the creature, which softens its actions both to good and mixed results. Coming from a Mexican man who grew up feeling alienated and loving monsters, of course this is the result of his view on Frankenstein. I for one enjoyed it and urge people to make their own conclusions about the work.