According to a recent double-blind study in 24 healthy volunteers comparing 2C‑B (10, 20, 30 mg), 125 mg MDMA, and 25 mg psilocybin, overall intensity was highest with psilocybin, followed by 2C‑B 30 mg, with MDMA slightly lower; lower 2C‑B doses were closer to placebo.
Psilocybin produced the strongest positive, mystical, and perceptual effects, but it also showed the highest levels of anxiety, nausea, and other unpleasant effects. MDMA tended to score lower on anxiety and distress. 2C‑B 30 mg sat in between, showing clear psychedelic features with fewer unwanted effects than psilocybin.
On “high” ratings, MDMA was often a bit higher early on, while psilocybin lasted longer. Psilocybin most strongly altered visual and auditory perception and was linked to more ego dissolution; 2C‑B 30 mg showed moderate changes; MDMA and lower 2C‑B doses were subtler. Socially, MDMA and 2C‑B 30 mg increased openness and closeness, while psilocybin also did so but more often came with a wish for solitude and introspection.
Some people discuss combining MDMA with psilocybin, sometimes called a hippie flip, and you can find a practical overview here: this article. Evidence is still limited and combinations add complexity.
Hope this summary helps.