Neither. Your question is akin to asking which type of drink is better than water to consume all day, Sprite or Cola? Are those our only options?
Socialism is a symptom (not a system) omnipresent in our oligarchic version of capitalism (examples abound). Our implementation of capitalism fails because it is not subjugated to the kinds of freedom that would otherwise quickly erode any impending oligarchy. And to loosely quote Margaret Thatcher, socialism cannot exist without capitalism to pay for it.
“A free people [claim] their rights as derived from the laws of nature, and not as the gift of their chief magistrate.” — Thomas Jefferson
Both “systems” of capitalism and socialism violate the relativity of freedom assigned to us by the laws of nature and thus are false proxies of our ability to expand the fringe of human ingenuity continually—an ingenuity otherwise designed and paired to meet our evolving equilibrium with nature.