This hagaddah does a wonderful job of synthesizing the story of Passover with the elements of the seder. This year, we were just the 3 of us so we could totally focus the seder towards my daughter, who just turned 6. In the days leading up to the seder, she wanted to go through the haggadah for 2 reasons: it really reads almost like a story book (and hence is fun to read), and it's very interactive (with songs for both the preparatory activities for the seder, and for the actual seder). This haggadah has the gorgeously rich illustrations of all Sammy Spider books. The simple songs that appear throughout are set to the tunes of well-known children's songs(like London Bridge).
Some things that were very nice extras were: after telling the Passover story, it then has 2 pages dedicated to the answers to the 4 questions! (Hagadas normally ask the questions but don't have a specific place for reviewing the answers.) The section for the plagues was child-appropriate, focusing on just 4 of them that didn't involve death or blood(frogs, lice, locusts, darkness)and then, tactfully, reads, "Finally, after the last plague, he told Moses: Moses, Moses, I finally agree. Moses, Moses, your people can go free!"
I was excited that my daughter could herself read a lot of the hagaddah out loud and be a real participant. Next year we will see how well we can incorporate the use of this hagaddah into a traditional, big seder where the grown ups are still using grown-up hagaddahs. Truth be told, I felt that this seder, while not including the commentaries of Rabbi Gamliel and such, had a big advantage for all ages: the salient aspects of the seder remained the focus. I believe that all the "required" elements were there (except washing hands), and they were center stage. To have a child who participated willingly and eagerly meant the world to me. Around the time of Passover, a friend asked my daughter what Passover was, and as she answered the question, I was floored to see that she had indeed grasped and retained the contents of the story. This would never have been so, had we used the adult hagaddahs this year. They say that the seder is supposed to be for kids/kid-friendly, and this hagaddah really makes it so!
I also recommend Richard Codor's Joyous Haggadah. We used some parts of this one, like the songs after the meal (which is the one thing that's pretty much absent from Sammy's hagaddah). In the next few years, we might switch over to this one as my daughter's reading skills increase and I'm more comfortable discussing "death of the first born" with her.