Is SPY or VOO better?

Could you possibly elaborate on the question of whether SPY or VOO is a superior investment option? Could you discuss the key differences between these two exchange-traded funds (ETFs)? How do their portfolios differ? What are the risks and rewards associated with each? Could you also comment on their performance historically and how they might fare in the future? Additionally, how do they fit into different investment strategies? Lastly, could you provide some guidance on which one might be more suitable for a diversified portfolio?