I have the Master X (3+5) for the Mix Systems ( TDM 1).
I bought the Master X 3 in 1999, then it was updated a few years later to the 5 band version. Even when not using so many bands, the 5 Band version sounds better to my ears.
I use it weekly, but most of the time I can not use it with the linear/flat curve. It seems it hypes the 2k-8k content.
Frankly, I prefer its limiter section over the L2 plug-in.
I played a few hours with the MD3, but was not convinced it was a major imrpovment. I am waiting for the new PSP limiter but might also take a look at the Ozone .
Pendulum OCL2 does the heavy work, when employing single-band compression here.