It is pricey to get in! It was okay, we are glad we went though. It was tough leaving the Disney magic and great customer service. To be honest, I felt as if the place was dirty, and some of the workers had an attitude. Now, if we had not been submerged in Disney for the previous 7 days, we may not have even noticed, but going from bliss to Kennedy we did(both my husband and myself).
You can contact your congressman and see if they have any free tickets left. If so, s/he will put you on the list, and when you arrive, just show ID, and it's free. Not sure when you are going, and they have limited tickets per rep, at different times throughout the year(at least that is what we were told in CT).
My son is very interested in space travel, so he loved it. He was 6 1/2 when we went, had no complaints, liked it as much as Disney in fact. The simulator is really really cool too. I would say it is worth going to, and even better if you either have a coupon, or if it's free. I'm curious as to other responses now too.