I did one photobook and I have to start working on another one (soon!). The books are really nice; I would probably suggest trying it once just to see how you like it. The appeal for me is the photopass pictures already uploaded online vs. uploading them manually at another site, the Disney clipart, and the extra "postcard" type pictures available to use in the book. I think you can add on two pages for like $7, so it's not too steep if you want more space. My only real complaint is that while I like the quantity of clipart, there isn't very much variety. There's really just Fab 5 and princesses. No Pooh, no Toy Story characters, no pirates, no Figment, hardly any park-related art. There are some backgrounds of the park icons, but the only park-related clipart I found was Minnie building sand castles shaped like the park icons. And I thought that was awesome... but it was the only one. I ended up re-purposing Adventures by Disney stickers for Animal Kingdom and World Showcase, which worked pretty well. Don't they know this is primarily a theme park product?
If it sounds like I'm complaining too much, I really do like the books. I think it would get old after a couple times since there aren't that many different characters to decorate with, but you should definitely try it.
Here are my tips:
1. I think the most photos per page on a pre-set layout is 4, but you can definitely fit more than that on a page and still see them well.
2. Try taking some pictures of your own to use as backgrounds. Leave a lot of "empty" space, like sky, water, or crowds so you can cover it up with pictures instead of covering up, say, the Castle.
3. The photobook builder will steer you away from putting pictures too close to the edges, but you can make it do it if you really try. This is good for the edges on the outside of the book, but follow their guide on the inside edges, so you don't lose half of your picture in the binding.
4. I made one group picture where I put one of the characters' clipart hats on everyone. Minnie's bow, Donald's hat, etc. People really like that picture.