LSD has given me the most clarified mental view of my immediate reality. Mushrooms tune me into nature and my physical body more than any other drug. DMT has given me experiences that are the least relevant and most difficult to integrate into my daily life, but which seem to be most relevant to my soul. These effects are all present in all three of the drugs to some extent, but I think this is where the strengths are in each individual substance, at least personally.
I guess I'd have to say DMT, since one incredible DMT trip is essentially the reason that I believe in God. But it's still up in the air, since on the day-to-day I don't really think about my DMT experiences that much. They are mostly like these isolated gems of memory that give me hope and appreciation for the universe when I need it the most, but I honestly have a difficult time applying them to my life.
LSD makes me really introspective, intellectual, and creative but I have a hard time deciding if my lysergic insights are truly enlightening or just parts of my imagination. Probably the most enlightening drug when it comes to music, art, and other aspects of life that are definitively human.
Mushrooms give me the most enduring insights about my physical health. When I take them and the initial discomfort passes, I usually feel very in tune with my body and the energies of nature and come out of the trip feeling revitalized. So... I think mushrooms are the most valuable in regards to my development, but DMT is probably the most enlightening overall, for reasons that are pretty hard to describe.
This is all best case scenario, not all my trips have so delightful 8( but even the bad trips have been enlightening in a sense