Tim Sale's art for this book is gorgeous. I love his more bestial, almost ape-like take on the Hulk. Though he mentions in the back matter of the book that he doesn't have as much of an emotional investment in the Hulk as he does the other Marvel characters he's worked on, I feel like his cartoony-yet-dark style is better suited for the grotesque goliath than it is for someone like Daredevil.
This would be a 5-star review if HULK: GRAY was just a showcase of Tim Sale's art. But Jeph Loeb's story gets in the way. The main thread of the story is overlaid by a dialogue-heavy framing sequence between Bruce Banner and his psychologist friend, Leonard Samson. The book's conceit is that it's really Bruce in the modern day, telling this (possibly misremembered) tale from his early days as the Hulk. Loeb has used this trick elsewhere, and the framing dialogue comes so thick and overbearing that it essentially means the reader is reading two stories at once - often in the same panel. This would work with a more layered, complicated story, perhaps, but Loeb isn't up to that. What we get is the Hulk smashing the US Army and a bunch of dialogue (most of which could be charitably called "filler") pasted in boxes over the top of that. This book's two stories get in each other's way.
I should make that clear. I don't so much have a problem with the story itself, but the way it's presented. It's a chore to read, and considering the subject matter, it really shouldn't be.
I do like the bit at the end where Banner has a revelation about his relationship with Betty Ross. That was the only bit of near-brilliance in an otherwise tepid story. It's too bad Sale rarely collaborates with anyone else, because I'd love to see him work with a writer who can keep up with him.