My opinion about mushrooms vs LSD is a bit different. Even though I have had two bad experiences with LSD - one on the far left hand side of horrendous, I would still say that all other things being equal, Mushrooms are far more potent in the physical sense than LSD. LSD, even in a bad setting is a smooth ride, imagine a big cushy cadillac where mushrooms are a tough high standing 4 x 4, each bump in the road is magnified and the seats are hard and unforgiving. I can always be sure that I am on the manic side, the wild and unpredictable side when I take sizeable doses of Mushrooms - I consider anything over an eighth to be heroic and have never taken much more than a quarter over the course of a day. To tell someone that if they have taken LSD, they will be fully ready to take mushrooms is a bit disingenuous. Mushrooms are their own beast. Mushrooms are alive, they are a presence that you place into your mind, they can be companion or nemisis but they have their own conciousness where LSD is simply a powerful drug.
I have found that a truely heroic dose of LSD is still not as intimidating as a heroic dose of mushrooms. I respect both drugs but I have reverence for for mushrooms that borders on fear, always. I treat it as I would undilute acid or caustic solutions. Mushrooms are the mirror and you tread lightly when it is possible that mirror could be a reflection of yourself at any time for any reason. And... no one is immune to the effects of that mirror on the soul.