I haven't posted for a while here.
Since I got in a business photographing weddings with a friend couple of years ago it's been going well and *knock on wood* I hope it will continue since we're doing our best and everyone has been extremely happy with the photos.
Anyway, I used to have E-5 with SHG glass and while it was great most of the time, purchasing OMD was really an eye opener.
My firend/business partner had Canon 5Dmk2 and he was never happy with it's AF.
So, several months ago we decided to change the entire gear line up and get Nikon D800/D600 combo since it seemed like the best thing on the planet if you believe the internet
Anyhow, we first got D800 and few lenses, among them Nikon's new 85mm 1.8G which everyone is raving how great it is.
It's not, in fact it's quite bad (lot of vignetting and CA/PF at wider apertures).
Also, "famous" Nikon AF was less than impressive to me, friend thinks it's great (especially after 5D2), but to me OMD has far better AF, more accurate and faster in lower light plus it doesn't make a difference which AF point you choose.
To cut the story short, I decided to get OMD for myself (again) and skip the D600 and few other lenses, but we'll keep D800 and that way we'll have best of both systems.
Plan is to get OMD, 7.5mm fish, 9-18mm, 25mm 1.4, 45mm 1.8 and 75mm 1.8 and for D800 we have 3 Sigma lenses - new 35mm 1.4, 85mm 1.4 and 70-200mm 2.8
Having used D800 for a few months it didn't work for me at all. It's ergonomics are quite bad for such a large camera. Someone mentioned how E5 and D800 were roughly the same size - it might be but using D800 is a pain compared to E5.
Grip is too small and not deep enough, buttons are horribly placed, ISO and WB buttons are really hard to access and use.
It is true that D800 can offer amazing image quality, but the problem is just that - can.
If you're using tripod, base ISO and/or shooting in pristine conditions with the most expensive lens it's output is unmatched.
But you need to print huge or look at photos at 100% on screen to see that.
In real world conditions, D800 rarely has an edge over OMD, most of the time it doesn't.
For instance, in order to avoid ugly CA/PF using 85mm lens I have to shoot using f4 (and to get enough DoF for portraits).
Compared to OMD and 45mm which can be used wide open, you gain 2 stops or so.
D800 is also extremely sensitive to mirror slap and any vibration will give blurry images, so minimum shutter speed I need for 85mm lens is about 1/160 in order to guarantee sharp shot and minimize shake blur.
When I use OMD I can easily have 1/60s if people are posing or standing in place - not running around, even with lens such as 75mm which gives field of view as a 150mm lens.
At the end, I'm using 3-4 stops lower ISO at which point OMD trumps D800 in image quality, or most of the time they're pretty much on par.
So... I don't wish to bore you that much with my rant, I just wanted to say that Olympus makes some really good gear and that you shouldn't get dragged into hype.
Realistically, D800 is too much of a camera in some ways (resolution), but pretty disapointing in many others especially considering it's reputation and price. It's really only worth it if you're doing 1m+ prints regularly and you're using stable tripod and best glass available.
In real world, there are much more important things than sensor size or number of pixels.