I did not particularly enjoy the methylone/MDMA combo. I have tried it simultaneously, and I have also tried it starting with one and then taking the other later, and vice-versa. It's somehow "dirtier", with a rough body feeling, excessively high body temperature, and due to the short duration of M1, if you first take MDMA and then 2 hours later M1, there is a chance you will crash harder than on either drug alone. Apart from that, inititally it's quite headfuck, I was uncontrollably "happy" - but the crash, oh oh oh! Also it made me euphoric to a degree that could have easily led me to make unwise decisions.
Regarding MDPV - it isn't that short-acting, I think. Though I also wouldn't combine it with other things except alcohol.