There was a time, when the name Jeph Loeb meant something. The guy who wrote Long Halloween and Hush storylines for Batman was brilliant. Todey it seems, Loeb lost his way. Hulk: Grey is from that time, when you cold trust Loeb.
It's competent and entertaining. It is not exeptional or brilliant, but it's solid. Loeb did not bring anything new to the Hulk mythos with Grey. It's not as meaningfull for the character as Blue was for Spider-Man. But it's good fun.
Tim Sale on the other hand is as good as ever. His one of the best artist in comics today. His take on Hulk is exeptional. I dont like the big culturist/ wrestler/ superhero type of Hulk, that is Marvel's house style. To me, Hulk is a monster, a creature from nightmares and Tim Sale captures this perfectly.
What makes Hulk: Grey special, and what reviewers often write about, is... the disney charm to the story. It's like a Disney movie, with Betty Ross as disney princess. It's defenetly worth picking up for that.