I'd get acid because I've only ever been able to find it for sale once and I wasn't able to get as much as I wanted. Mushrooms are always around and when they're not you can easily grow your own. Good luck making your own LSD.
I prefer a trip on mushrooms but i'd still get the LSD and stick it in the freezer as you can pick shrooms in the wild or grow loads yourself for pretty much free and coming across the opportunity to buy LSD is rare for myself
This is ultimately a question of taste akin to asking whether salt & vinegar or smoky bacon are the best flavor of chip. (Salt & vinegar obviously the correct answer)