I assume you're referring to Matthew Chapter 16 verse 28? The same incident is also in Luke and Mark, from memory. At any rate, it's worth noting the event directly following Yeshua's statement ("There are some standing here who will not taste death till they see the Son of Man coming in His Kingdom" - New King James translation) is the Transfiguration, so his words could have referred to that incident, not the events of Revelation.

But yes, John certainly had a mind-blowing experience. :)