For me, AMT produced very little mental effect
I thought that AMT was one of the most beautiful and introspective drugs I've ever encountered. OK it doesn't suddenly drop you into psychedelic freefall, the way some tryptamines and large doses of LSD does, but in terms of aesthetic appreciation of beauty, and the empathic effects that allow you to feel close to the beauty, the only ones that are even in the same league as AMT are mescaline and MDA/MDMA.
They are the only drugs that have ever produce something akin to "a state of grace" in me that was so strong that I cried as I was so connected to the world, other people, and their sense of joy at being alive.
For me, the most "all the sights and sounds of the carnival of the absurd, but without feeling part of it" drug is 2C-I, unless taken at doses I don't feel happy with for health reasons (a one off 25mg IM dose).
2C-T-21 is pretty much free from visual effects, but it doesn't have anything like the weight you'd expect from a psychedelic (more a walk in the sunshine rather than an audience with god!)
As for the most intense visual effects, accompianied with insights into "life, the universe and everything" (thank you Douglas Adams, for the phrase that sums it all up), I feel that the prototype psychedelic (LSD) has yet to be surpassed