What "truth"?
I wish people would stop trying to insist that M43 is all things to all photographers.
It's a great format, and it has many advantages in many situations. But, so does FF. And you do both a disservice by trying to equate them.
Guess what? Most cameras are pretty good these days. But if you are shooting in situations where one system is stronger than the other, then you will make yourself utterly nuts trying to get what you need from the other system.
Case in point: I use both M43 and FF. I can take my GX9 out with the PL 100-400mm, and walk around with it in the woods, and get bird and other wildlife shots without arguing with my back or wrists about the weight. To get that reach on a FF, I would be looking at over 4lbs of lens, vs 2 (with a much lighter camera body). Big difference.
On the other hand, for delicate flower work, the FF has an advantage. I can shoot at ISO 800 without even thinking about noise and loss of detail, and the tonal and color gradation captured by the FF sensors is just better in these situations, as there are enormous color variations in flower petals that are very difficult for smaller sensors to capture (this is where more photons really matter). M43 can be very close in just the right light, and at base ISO it's very good, but anywhere north of that in this kind of shooting tests the limits of the system, and FF makes much more sense in this case.
So, these comparisons mean...nothing.
Pick the gear for what and how you shoot, and be happy.
-J
