I took LSD on several occasions, magic mushrooms and and have also done deep meditation. This was all around twenty-five years ago and I don't even drink now. But my experience, since you asked...
LSD: Although looking back, I can't believe I used to take it, I have no regrets. For me it definitely did open my mind to different ways of thinking and having tripped pretty hard, I am left with the irrefutable knowledge that there 'is more' - whether that means there is more to our brains, our universe or different dimensional ways of experiencing things, I am not sure. But I am glad to have had the experiences I did. Some of my trips were just 'fun' - mild and often shared hallucinations (riddle me that!) and laughing that was definitely extreme and hysterical, but no less good for the soul for it. I have had more introverted trips where I felt more solitary and wanted to look at things, think, listen to music and allow the trip to take me wherever it will and I have had a couple of less pleasant trips where I understood the dark side of taking acid. Luckily I was able to bring myself back round though grounding myself (it will pass), listening to music and sharing my feelings in real time with people who understood and could help me back.
MUSHROOMS: Similar levels and variety of hallucination and visualisations. I remember feeling like I had experienced what it must be like to have synthesia and also experiencing the most beautiful and magical colours, lights, shapes and sensations of warmth and safety whilst in a forest after a night out. I definitely felt as though a door opened in my brain and has never fully shut - not in a scary way - I feel completely normal and grounded - but more of a 'once you've seen it, you can't unsee it' kind of way.
Deep meditation. I have mildly felt the euphoria from meditation but not on the level that I felt it on drugs and I didn't ever visualise. It was more akin to taking ecstasy than a hallucinogenic.
FWIW I don't think I am 'cool' for taking drugs in the past, I wouldn't advocate and I am the most boring square now, but I am glad that I experienced the things I did as it has given me more empathy and a more open mind to the possibilities of what could be going on in other peoples minds. It also makes me a bit excited for what we might discover our minds are capable of in the future.