What is the best ETH network?

Could you please explain to me, in a straightforward manner, what is considered to be the optimal ETH network? I'm interested in understanding the criteria that determine its superiority, whether it's related to transaction speed, cost-efficiency, scalability, or perhaps a combination of these factors. Additionally, I'm curious about the current consensus among experts and the community at large regarding this matter. Could you also provide insights into any potential challenges or limitations associated with the best ETH network? Thank you for your assistance in clarifying this topic for me.