I loved it. It had been quite a few years since I'd last read the original comic, and my copy was on loan, so comparisons with the original were tricky, but in hindsight, the story's adhered to quite closely, apart from a couple of major deviations, concerning Tristan's time with De Niro's pirate, and the ending itself.
For the pirate sequence, Goldman's effectively transferred a learning experience Tristan undergoes when he first enters Faerie to later in the tale, and makes him learn things that are more suited to action. For the ending, Gaiman's original is more mature and forgiving; Goldman's provided more closure in the traditional Hollywood style, which takes some of the bittersweet texture out of it. But it still works well.
I found Ricky Gervais to be annoying, but then, that's nothing new. The brothers in their quest for the gem were marvellous, though. And Michelle Pfeiffer was fantasic.