DXM is insane. I've only tried it twice. One time with LSD as well.

To give you an idea of what the LSD/700mg dex trip was like...
I was sitting in a room listening to some music with a couple of friends. I closed my eyes to venture off into a type of 'lucid dream.' I was in the exact same position as I was before I closed my eyes. Same music. Same people. Same room. Same smell. Same feel... It was kind of cool. Then I opened my eyes and returned back to 'reality.' When I opened my eyes, everything was normal...except I was looking down on everything...including my own body. Then as I watched a friend nudge me, I REALLY opened my eyes and I returned to my body and actual reality. It was intense. I don't do DXM or LSD after that trip. Complete loss of reality in a way that I have never experienced nor do I want to ever experience again. A couple of weeks after that trip...I still doubted if I was really awake whenever I woke up from a dream. X_X