Sparkle = Mephadrone?
I have never taken MDMA, as i can't get hold of it at all, so i don't really have anything to compare it too, it's deffinately alot stronger and better than BZP and all other legal highs i have tried, I have a freind that has taken MDMA and sparkle and assures me that sparkle is good but not quite as good as MDMA, though he's only taken MDMA once so i don't think his opinion is entirely reliable.
From how you have described mephadrone it seems pretty simmilar to "sparkle" basicly if you do it in small amounts say 50mg lines every hour it just keeps you buzzed, where as if you do alot in a short space of time, say two 100mg lines in 10 minutes you get an intense rush of euphoria, feels like everything is entirely new and you've never seen it before, all senses especially touch is multiplied by about 1000 times, there's no comedown, but after about an hour when it starts to wear off you start to get annoyed that you're not up so much as you were before as it's so good, then after you still have the physical effects of cold air feeling tingely gurning, urge to smoke a hell of alot.
Weed seems to kill the annoying feeling in the back of your head that it's not so good anymore, makes you feel empty and have the ability to look at anything for ages without ever really working out why it's there when mixed with weed though.