Hi there! We are going to use WP Animals and Their Worlds next year with our 5yo dd. I have the guide now, and I can tell now that its going to be a fabulous year! Our family has used several WP programs over the years, and we have always been thrilled with their quailty. Their exclusives, the books they choose, and the extra stuff - weblinks, etc., are all well thought out. Everything is laid out for you, down to which weeks you will need which supplies for projects. I've tried a few other programs to save some money, but I keep going back to WP because the kids and I love it so much.
Did you see that you can download a trial week of the Animals program? Read through that and see what you think. They have e-book options for their exclusives now, which brings the price down a bit, and I have had luck finding the scheduled books either at the library, or used. As far as the shipping issues go, they were a small start-up company and did have some kinks. I think over the last few years they have improved on the issues others have seen. I know there were 3rd party shipping/printing issues. To combat that WP now publishes many of their own titles, and I'm told (by them) now only orders from limited suppliers. My last orders came through timely and complete.