After many sessions of varying lengths and quantities with MXE, I can say that it is the single most unpredictable substance I have ever tried. Nothing else has produced such a wide variety of effects (from the same batch); stimulation, confusion, feelings of connectedness, drunkenness, extroversion, feelings of isolation, introversion, clear-thinking, powerful physical pain relief... I've stopped trying to plan my experiences with it, because it seems to do whatever it wants me to. It's also interesting how different the effects are after repeated uses. With a lot of substances I find that the first few times are the best and then the effects become dulled - it loses some of its 'sparkle'. But with MXE I find the effects are quite different as time goes by and my experience with it grows. It's not as immediately euphoric as it was at first, but I get a greater sense of being 'tapped in' to neurological evolution which is ultimately more interesting. I'm not saying that I am actually tapping in to such a thing, just that it feels like it. It's bizarre. I like it.
One of the most uncharacteristic of my MXE experiences was a powerfully stimulating trip that was far greater in intensity than my (admittedly limited) experience with stimulants. Compulsive movement, jumping, dancing around, feeling weightless, visual distortions - an incredible combination. That only happened once. Again, from the same batch of MXE as every other experience I've had. I wasn't using anything else at the time. I wish, however, that I could recall what other every day things I had consumed (medication, food, energy drinks, etc) on that day, in case something created the conditions for such a speedy trip.
I also have found it to combine well with other substances (opiates, alcohol, small amounts of stimulants: it should go without saying that such combinations are not safe and great care must be taken when doing so - better yet, don't combine MXE with anything), but that MXE will overpower other things fairly easily.
MXE would have to be the best novel substance I've tried, considering the range of effects it can deliver and its versatility (social enhancer, mind exploration tool, pain killer, boredom smasher, etc). Key thing, as has been noted many times before, is not to use it too frequently.