I have to agree with Barry. Irrespective of how many here insist he's wrong, some of these companies may soon be headed for a new round of trouble.
The OM-D is impressive (most of it anyway) and combining it with a few small lenses sure beats carrying around 20-40 lbs. of C/N gear. As appealing as small ILCs are, and they are extremely appealing to me, I've never been willing to enter the 4/3 (m or not) market; I just don't see it as practicable long term and I can't forget the disgruntled Oly users that were abandoned in the 4/3 market.
I know people will cite that the m4/3-4/3 market is still with us and getting better, but the possibility of its demise is real (see Pentax FF rumors). Hence, I'm more inclined to buy an APS-C solution than 4/3 or m4/3 because it just makes more sense long term - and the sensors are dirt cheap to produce.
As with film, sensor real estate matters, and if Nikon releases a D600 at $1,600 or something south of $2k US, I believe people will buy it in large numbers, putting pressure on all markets, and *possibly* the Oly/Pen/Panny/et. al m4/3 markets. I realize that it's (D600) not offering ILC size advantages, but for those that want good/great IQ in a small'ish package, it could attract many people. The other effect is that pricing pressure makes the cropped APS-C offerings cheaper and more attractive.
The real question is how many formats are required, which provide better results, and what are the corresponding prices? I'm betting on APS-C to be the survivor, but we should all know more in the Fall.