Ermahgerd! Merth Brerwn! I tried MB over some purple bases because the purple shift is not obvious on me. It is there a bit, but it wasn't obvious to me until I swatched it next to Hocus Pocus and Nebula. Next to MB, HC looks more neutral (although MB isn't super cool or anything) and Nebula looks warmer. MB is definitely brown or at least a warm grey taupe on me. I'm NC 5 btw. I couldn't get good photos because I'm in the Dallas area where it's decided to be cloudy for once.
In reality the shades are lighter and warmer than in the pics.
The two little swatches on the top left are HP and Nebula but they just didn't come out right. Top left- MB heavy swatch, top right-- MB blended swatch; Middle left--MB over Maybelline Color Tattoo in Painted Purple (this looks really nice in person; it brings out the purple more without darkening the shade too much), Middle right-- MB over Half-Wild paint pot (fail); the very bottom is MB over Imaginary paint pot but that didn't really work out. These are inside swatches.
The outside ones are a little more color accurate but still dark:
Overall I'm really pleased with MB and I'd probably get a bu if I could afford to right now. It's really soft and reasonably pigmented to me.