Imo-
Mushrooms are kike a roller coaster. You get pulled along for the ride with all it's ups and downs. They are more organic feeling.
Lsd is like riding a bike down a long, winding, groovy path. LSD is sharper and more "electric"
Trying to explain psychedelics however is an impossible task. Like explaining sight to a blind man. You just can't possibly have any grasp on what they're like until you do them yourself. You can definitely prepare and educate yourself but it's not like most drugs where I can describe to you the effects and you can compile them and get a sense for what it's like. Psychedelics mess up your perception and make connections where there were none before and it's impossibly difficult to describe to somebody who doesn't know.
Don't let that one guy scare you off shrooms. Be smart, research, start low, have a safe environment, see for yourself. Or not. You don't have to either.