I wasn't disappointed either. For a novel that is essentially a love story (man has genetic disease that results in regular travel back and forth in time, time travel mostly takes him to the environs of future-wife as a girl or old lady, man deals with this) it does it surprisingly well.
Unfortunately, the reason most people read time-travel novels is that you get major contradictions that the author has to try and sort out. For instance, Isaac Asimov did a whole number of stories all the lines of hunters going back in time to kill dinosaurs, who then return to find the world has changed in major ways. There is another classic genre along the lines of the go back in time and kil (a) Hitler (b) Your grandfather (c) Yourself.
But as a love story with a extremely new, interesting and bold idea the novel hangs together very well indeed.
However there are some criticisms (not least the bad spelling of traveller). A book about time-travel that fails to mention anything about current/past events, politics, newspaper headlines or fashions with the exception of a rather interesting taste in music, is one thing. A novel that ignores all these things, but only mentions 9/11, says more about the US psyche than any number of mori polls could.
Additionally the book is thoroughly Middle Class. It's filled with middle class angst about relationships, babies and art. It reeks of middle class feelings of unworthiness and frustrations. It cries out for someone to be evil, rude or angry.
Nevertheless, it's a great book. But I bet there are book clubs the length and breadth of Britain arguing over it. Over a nice Bordeaux.