I haven't touched anything apart from weed in a long time but MD was awesome.
I remember one time I went out with a mate on MD for a dubstep night and they get in some extremely intense bass speakers for this night. We both drop too much before we got in (about 220mg each and neither of us had touched it in a while), when I was in there I couldn't fucking breath because the bass was so insane, it literally disrupted my chest in some way.
Anyway, my buddy wasn't feeling to good so I head to the toilets with him. There are people in the stalls already so we're just standing there waiting. Both of our jaws rattling, our eyes like anime characters when all of a sudden he just projectile spews all down my fucking top. We decided that was probably the best time to leave.
There was another time we went out in the same city, there was about 8 of us but only 3 of us dropping. The same friend from the last story was absolutely gubbered again (Sudden Clarity Clarence looks like a spitting image of him when hes mangled) and I mean really mangled. It was hard enough getting him TO places nevermind getting turned down at every single place because it was obvious he was totalled. After a while of searching the one place that would let us in was a strip club. In the end we basically paid halfs to sit opposite each other while two bitches went between giving us lapdances and licking each other out - his lost, slevering, sweaty chattering face was absolutely priceless.
As for permanently changing me? Yes. I think everybody changes slightly once they have felt that intense euphoria. The first time you realize how good your body can truly make you feel it opens your eyes a bit.
Another thing I found was when we used to do it all the time, everybody was open with each other. You could sit with a group of random people all night and become the best of friends, discussing all your innermost thoughts. After I stopped taking stuff all the time I had to re-evaluate what the appropriate way to act/talk in certain situations is instead of just being open about everything.