Upload & Sell: Off
I agree with Bobby. The major limits on the OM-D's capabilities lie in a really marginal AF system and the lack of a decent long lens. In terms of the AF, it is not just the continuous AF that is marginal, it is the size of the focus boxes. If you are used to working with pro cameras this causes a lot of frustration and limits the Oly's ability to function effectively in many arenas where speed and focus accuracy at wide apertures are paramount.
This was particular a problem today when testing a Panny 100-300. I wanted to focus on butterflies and the camera wanted to focus on the flowers behind them because they dominated the chosen focus box on a regular basis. Yes, I could have zoomed in but the butterflies would be long gone by the time I got done futzing about. I doubt that smaller focus points can be a firmware upgrade but boy would it be nice if they could.
On the long lens side, I was very surprised by the Panny 100-300. It is very good at all focal lengths when the subject is within 50 feet. After that it goes downhill quickly and by 200 feet it is just rubbish. 300mm at 200 feet has smeared detail that looks like an impressionist painting. Will test again tomorrow and it may just be this lens but qualitywise, this is P&S territory as far as I am concerned.
The above negativity should not be taken to be as being more than a comparison between the OM-D and a decent DSLR. Both have advantages and disadvantages.
I could have written the above myself almost word for word. For context I also have a D700 and a fair set of lenses to compare the OMD with. I was out today doing a bit of casual birdwatching on a hike carrying the OMD with the Panny 100-300 on board (nb; the Capture Clip is the best hiking accessory I have ever encountered). Most bird shots are, of necessity, at maximum fl and usually quite distant. I have seldom had great results under these conditions and used to put it down to a combination of factors including the IBIS not really being up to the job at an equivalent 600mm. However shots at closer range are vastly better.
The af box is indeed horribly oversized and a software blunder means that when you switch from the ridiculous default box to the smallest size the histogram vanishes. I've got used to setting the exposure and then stabbing a Fn button to get the reduced size focus box, but ideal it ain't. The af is pretty patchy too, even in good light. You quite often have to resort to focusing off-target first, sometimes even when there seems to be an adequately contrasty target in the foreground. This is definitely worse with Panasonic lenses as far as I've experienced.
The matrix metering on my OMD is odd too, almost always requiring substantial +ve compensation, frequently >1 stop, but somewhat unpredictably. I'm so used to this that it scarcely bothers me. And you can happily pull the RAW files an astonishing amount.
My D700 doesn't get as much use these days. Whenever I pick it up I can't believe that I've carried it as far as I often have.