I think the issue with LSD for beginners is how long it lasts. Mushrooms lasts a 5-6 hours on a full stomach, 2-3 hours if you blast them powdered on a empty stomach. LSD even a small dose is a 12 hour commitment, add another 12 hours per 1000ug. Source: Took a lot of psychedelics and even more trip sitting.
EDIT As for trip potency, they’re both too different and too similar to judge. Similar in terms of visual distortions, different in terms of colour, both very colourful. LSD has a stimulant-like MDMA body high, mushrooms has a body high that’s hard to describe. One is an emotional rollercoaster, the other is a different emotional rollercoaster. One has you speak to aliens, the other has you speak to God.