I used an M390 Ritter Grip and a s30v PM2 everyday for four weeks while on a training exercise. The knives were used for food, rope, whittling, cutting wire and cord, cardboard, and general chores (opening clamshell packaging, zip ties, cutting LOTS of pesky branches, and preparing terrain maps). I switched the knives out every other day (to keep myself from getting bored, not for testing purposes.)
The s30v did well, but was noticeable affected after the four weeks. It had shiny spots on the edge when viewed straight-on, could not cleanly cut office paper or laminating plastic, and really needed some care to be useful again (i didn't bring a strop or stones with me.)
The M390 also did well. There was one spot on the belly near the tip that was affected (small shiny spot), but the rest felt as sharp as day one. None of my tasks were inhibited by the condition of the edge.
The s30v is easier for me to sharpen (especially Spyderco's s30v), but the durability of the M390 was really impressive. I won't avoid a knife because it has s30v, but I will always show a preference for m390/20cv/204p after seeing the very real EDC difference.