My 5 yo son loves this program. I love it too. The aliens are always kind, and teach him so much about space and science. They do different places in the universe to help out others in need, and along the way there are wonderful lessons in humanity and science. He's learned things that even I didn't know. Concepts that I wouldn't really think to teach him like how shadows change throughout the day, what simple machines are and how they work (lever, pulley, incline plane).
At pre-school on his day to "share" he brought in a placemat with the planets and proceeded to tell all his classmates about the planets (he named them all), which one had moons, which are gas vs. rock planets, why Pluto is on the "maybe" list of planets and so much more. It truly amazed me, and all the other moms too!!!! I didn't know he was absorbing so much from this show.
He still loves it, but has seen every episode so many times and there aren't lots of new episodes being added. He'll now request other shows that are new to him. But we still come back to Zula Patrol and he is still mesmerized by Captain Bula, Molto, and Zeter. I don't let him watch the Star Wars movies (that many of his friends do watch), so having all this information about space levels the knowledge field for him. His friends might know all the Star War characters, but he knows about space!
I actually put it on every now and then for review. I'm hoping that he won't forget all the science he learned on this program.