I haven't seen it, but as far as I'm aware, its problems are numerous:
-Writer/director's live-action debut (Wall-E and Finding Nemo prior)
-Vague, meandering plot
-$100m spent on advertising even though they knew it was going to flop, just to keep the writer happy
-Poor marketing because the plot was vague
It's definitely a commercial flop, costing somewhere in maybe the $180 million region and so far taking in possibly $5m. However, I've seen a few people say that getting past the marketing mess and going to actually see it, it's not too bad. It's not exactly good, given that the man at the helm knows story inside out, and you'd expect much better, but it's watchable and reasonably entertaining.
The timing isn't particularly relevant- it was never intended to be a big summer/winter blockbuster, and the other movies from that same weekend all posted double figures, I think. The movie isn't like the book, they had to change the protagonist significantly in order to make a movie out of it. Some people who have read the books didn't like that at all, felt like they completely destroyed the protag, but others thought that it was a logical and necessary change in order to make the jump to film.
So, it's an individual thing, really. Personally I have no great interest in watching it, but I might read the books at some point, we'll see.