If you are after of showing something worthwhile, show me a comparison of the Olympus to a Sinarback in MS mode... that would tell me something...
A few months ago I spent several days testing an OMD-EM-5 Mk11 against a D800e and in the studio, an M22 (Jenoptik 22mpx 16-shot back, superior in my view to the 54H, due to its Dalsa chip vs Kodak. I believe Jenoptik also made the 54H for Sinar). The M22 was using Rodenstock HR lenses via Rollei shutters.
The OMD shone in multi-shot, but not astonishingly until I put the Olympus 45mm lens on it, when it practically sparkled. I was really impressed.
What people may not be aware of, is that when using RAW mode, the OMD produces a 64 megapixel image. It sharpens extremely well using deconvolution (can take more sharpening than I've ever used before). It has a softening of highlights as they go towards white, which is typical of dslr type cameras, but is annoying when the exposure is being carefully controlled.
How did the files compare to the M22 at 88 megapixels? Amazingly well. Not *as* good ... but for such a tiny camera/chip, I never expected them to be this good (when accompanied with very sharp lenses ... for example, the Olympus 60mm macro was nowhere near as sharp as the 45mm). There were some artefacts in the captures, visible at 100% which I have seen previously in multi-shot and I'm fairly hopeful that these will be addressed with firmware upgrades. There are some limitations which I'm sure will also be addressed ... sync speed for flash being a stumbling block for many situations (this may already have been improved?). I have some Schneider Digitars in Rollei shutters, from the days when MF chips were 35mm sized and I would love to have tested it with these, but I didn't have the time to try and hack something together (not having adapter plates and bellows etc.)
(I've been shooting multi-shot since 1999 ... so I have some experience with it).
Aside from the multi-shot aspects, the camera has huge promise and like Bob David, I'm intrigued with what the 'Pro' version will bring. Working with it is a delight, when one is used to a tethered view camera (Arca-Swiss in my case). The articulated screen is a wonder of engineering and the EVF is the best exposure meter I've ever used. I would like to have larger single-shot files. 16mpx is just a bit too small. 24mpx would be fine for me, especially as this would take the multi-shot files up to 96mpx (when using raw) and perhaps if Olympus adopt the back side illuminated chips, they'll be able to bump the pixel count whilst maintaining quality. On the other hand, I love the 'tiny-ness' of it, especially of the subsequent 'tiny-ness' of the lenses. Glass doesn't need to be gigantic to be great, as Olympus proved almost 40 years ago and continue to prove today.
The big downside of the camera is the same as all of these digital cameras ...
the menus and general UI is a total mess. Zillions of options which are mostly pointless, impossible to understand and well ... a total waste of time. I'd like them to apply some of their German engineering skills and logic to these and make them far more simple to use.