Well, do you want a traditional textbook or something a little different? If you want a traditional textbook program, go with Apologia or BJU. If you want something a little different, a little more literature based, go with SL. I've used both SL and Apologia elementary science. SL's science was really good, but I didn't like Apologia (partly because it's more of a textbook). So, to answer your question, I'd recommend SL science. I think SL science 6 looks like a great year. Blessings, Laura