I am just now finishing this book for the second time. The last time was about 12 years ago.
I liked it the first time, but I'm getting so much more out of it the second time through. I bought this copy from a thrift store. The previous owner has made comments throughout the book, and even a critique of it in the front cover - makes it kind of fun reading what he/she had to say and what they thought was comment-worthy.
One of this person's comments, which I've also seen in this thread, was that Pirsig didn't say anything that he/she didn't already know. I'm not sure why this should be a hang-up; as Pirsig mentions at one point in the book, 'people go to church not to gain any new understanding, but to rethink what is already familiar,' or something to that effect. Things always seem crystal clear after someone else has already laid them out for you. But I think it's nice to have have them refreshed, even if you already knew them.
I think it's just an all around neat book. A man who had much of his memories jumbled by electroshock therapy, in search of himself through his former writings and memory fragments, on a cross country trip on a motorcycle, dissecting his thoughts and relating them to motorcycle maintenance. His idea of Quality is interesting to me also.