Before I begin, this article covers something that is completely speculative at the moment. I don't normally write about rumoured products, but it seems that this is about 90% certain to happen.
When I made the choice of going mirrorless systems, I had a lot of choices at the time, but I didn't do it because of brand loyalties or changing from them.
First off I did this to take the weight off my shoulders with a compact system that could be both something that is in my bag all the time, or to be my very lightweight back-up. Of course back-up cameras should generally be the same system, I was less concerned about that when my entire EP kit with three lenses is less than the weight of my 5Dmk2 with a 70-200 lens.
Secondly, I wanted to also expand my access to other lenses from other manufacturers that the EOS system could not adapt. I bought into the EOS system originally because I wanted to be able to use both Canon and Nikon lenses on it. But although the EOS system is quite adaptable to other lens systems, I couldn't put my Leica rangefinder lenses on it. So the mFT system filled that void.
I chose Olympus over Panasonic because I liked the interface and also size/build. However after handling the GX1 the other day, I'm very impressed with what Panasonic produced (but I'm not going to dump my E-P3 over it). I chose this system over the NEX system as well not because of sensor size either. I could have easily gone to NEX and still have leica compatibility, but because I wanted a decent small form factor camera with decent primes that autofocused, the Sony systems didn't fit the bill (at the time). Even with the NEX-7 now, I still stand by my decision also for the simple fact that there are over a half dozen manufacturers making lenses for mFT.
I currently use my mFT system for about 20% of my work. I also for a case in point used it 100% of one job. Something that I enjoyed doing, but faced some serious limitations with my E-P3.
I'm attracted to the OM-D not because it is SLR like, but I'm hoping that what it provides is things that the E-P3 falls short of in production work. For street and vacation the E-P3 will likely still be great for those (and also a toss in my bag system), but if the OM-D is what I hope it will be, it will fill in the gaps that the E-P3 misses in my current workflow.
At the end of the day, the tools are important in your hand, but you don't see a carpenter use wal-mart tools. They buy quality tools that last, works in their job, and provides the best balance of quality to application of use.
I am a consumerist after all, but I also like to buy tools that fit my workflow best... is the best tool in your hand any camera? Certainly is, but if your job is to make quality pictures, you want to have the best tool you can afford for that application.
The family of accessories that are rumoured to be part of the new camera and two new lenses! You can also see how tiny the system is compared to the lenses which are all pretty small to begin with.