But is Rocket Lab a better space stock to buy than SpaceX? Founder leadership, but one with more focusSimilarities continue between Rocket Lab and SpaceX, with both operating as founder-led businesses. Another aspect where SpaceX and Rocket Lab need to be compared is valuation. Size should matter in valuation, meaning that a smaller company like Rocket Lab could be worth owning even if it trades at an expensive-looking multiple today. If forced to choose, Rocket Lab looks like the better buy right now.