Motivation in serving God

Peace and blessings,
My question is based on two premises:

1. All the answers I know to the question "Why keep God's commandments?" are based, explicitly or implicitly, on the assumption that keeping the commandments brings any good to a person. Indeed, a person will not be willing to accept a system of laws that leads to an increase in evil and suffering. (As I believe is also true of the Rabbi's theory of "philosophical gratitude").
2. God created evil in the world.

In light of the second premise, why should I trust God that the system of laws He has given is for my benefit?
 
(A possible answer to this question is a broad and long-term empirical examination of the effect of observing the mitzvot. It seems to me that such attempts have been made in recent generations, such as Rabbi Sachs in "The Great Partnership." But since this is a very complex system, it is difficult for me to see how a clear empirical conclusion can be reached here.)