The MAOI has a prolonging and intensifying effect, and has psychedelic effects of it's own. Smoking DMT isn't the same as eating pharmahuasca, which isn't the same as drinking ayahuaska.
That said, it is very, very rare for anyone to have a reaction. The quality tours have trained medics in the village, and the villages are jammed deep in the forest like some of the hippy tours.
Smoking DMT is a very clean experience. It is intensely visual in nature and completely cerebral.
Pharma/Ayahuaska is a heavy body load as you drift in and out of the altered state often called "hyperspace".
I don't really recommend the MAOIs because of the complications they can cause, and you can have just as spiritual of an experience without drinking their "jungle juice". haha ;)