Definitely mushrooms. Organics are always safer than synthetics. I've seen people take mass amounts of shrooms and always come back "to reality". I've seen people take mass amounts of LSD and not... No, LSD doesn't cause spinal injuries. No LSD doesn't create holes in your brain. As far as the "trip" goes, they both can go down hill pretty fast. They both can go up hill pretty fast too. It mainly depends on your environment and situations in your life at that time. If your in a place that you don't trust and dealing with a bunch of emotional issues with family, relationships, ect. it very well could have an effect on your trip. I find that shrooms are alot more relaxing than LSD as it's a dissociative and a psychedelic whereas LSD is a stimulant/upper and a psychedelic. Visually, I'd say shrooms are more "cartoony" or childish to me. LSD is more geometric pattern visuals and color altering. (Both are, but I feel like LSD is mainly pattern/color altering based.) It's only with mass amounts and a lot of trip experience when you get to the point of actual hallucinating. Head space is really what makes me like LSD more though. It's so much more of an intellectual high whereas shrooms is more of a synergistic body and mind high. Things feel more mechanical on LSD and more "flowy" on mushrooms. (I call shrooms my mental medicine. It allows me to figure alot of shit out that get me caught up in life that I have trouble deciphering sober ie: problems I'm facing at the time, situations I'm in, ect.) Don't get me wrong, I'm not saying it's like this for everyone, but that this is how my extent of psychedelics have been perceived by myself. It is VERY VERY dependent on the person that takes them. Psychedelics are not meant for everyone. Every mind is different. Use it wisely and with precaution.