I did most of my work this year with dt880s. They're clear in the sub and all the way up. They're light, they let your ears breathe, it's all good. The dynamic range is wide as hell, to the point of ear fatiguing. Plus spikey highs.
Not sure yet if I'd take dt880s over k240s, but definitely not over m40x, if you open them up once in a while.
M50x are even more mid-scooped, which is why I think of those as what you give artists and listeners rather than producers. Still, some of the best sound designers I know use mostly m50x.