We believe Speed-to-Value is the most important metric.
It does not matter if you are the first person to talk to a lead if you have no ability to deliver them anything of value. Therefore, it's more beneficial to be a valuable agent and contact a lead days later in an environment where most other agents will be contacting that lead right away, but delivering no value. When they pick up the phone and talk with you to receive value, typically their responses will be something like, "Where have you been?!"
If you can combine both speed-to-lead with speed-to-value, this is where you will get the most out of your lead generation.