If you read the comments below, you will quickly figure out that people either love or hate this book. As for me, I loved it, as I spent got because of it many hours in the company of a good boy, Archie, whom I got really attached to. When the book ended, I was so sad to leave him behind -- indeed it took me a few days before I could start with another book and this *never* happens to me usually.
If you decide to go ahead and plunge into Archie's life/lives, here's a tip : keep notes. The four Archies start at the same point, but over the years they go through different experiences (rich/struggling parents, married/divorced, public/private school) etc and it can get confusing after a while. You'll thank me later :)
Last thing I wanted to mention : if you can, read it in the audio version. First of all, because 800+ is very long to read so do yourself a favour and let someone do the hard work for you. Second, because the narrator is the author himself, Paul Auster, who has a beautiful deep voice that I couldn't get tired of, even after the some 38 hours of recording it took to tell the whole book.
Do it! It's quite a trip.