Thanks Mr_DMT!  The Shaman: I have only had stronger cactus experiences a few times, and only with alcohol (to stem nausea, ok and for fun and courage I admit!).  I often take smaller doses though.  I'd say cactus is less visual, but once you've eaten enough the visuals are more organic and can be more lifelike.  Ayahuasca is quite cartoony.  Cactus also seems less frantic.  It feels a little like MDMA, but weaker and without being emotionally forced in one happy direction.  I've never taken enough shrooms to be able to compare properly, I'm not really a shroomy person!  I think I went as far as it is possible to go with DMT, and I definitely did with salvinorin A (you pass out eventually), so I could compare those two to each other properly.  But I've yet to have a full on shroom experience, and I'm not sure I've had a full on cactus experience yet... most I ever had was 40g, which is quite high if it's strong stuff but some people do go higher.  I don't know what the maximum responsible dose is, but I do remember reading an Erowid report once when someone ate 65g!  Don't think that had a good time though!