Like anything else, some books we love, others not as much. I have a three year old, so we have a little over a year left to continue with the program (he turns four in a few months).
A little while back they switched from sending hard covers, to sending paperbacks (it's a free program, and they are trying to keep costs down). I understood the reasoning, but was still little disappointed. That was until the paperbacks started arriving. Books From Birth is full of geniuses. Now there's a small flap at the back of each book that gives specific instructions to parents on how to read the book with their child so the child gets the most out of the read-aloud. It lists ideas of things to talk about before the story, during the story, and then after the story. I'm a beginning literacy teacher, and even I find this little flap extremely helpful, and totally utilize it! It's like a little script right there for ya, so why not use it!
I think this was a brilliant idea, and I wish this was done with every library book as well... OK, how 'bout just doing this with all kids' books? It makes it so easy for parents and even teachers who might end up with some of these books in their classroom, since so many picture books get handed down as kids out grow them.