This is my first post and is a bit of a rant, so please forgive me.
All this testing is useless. Only YOU can decide if a back/camera will meet your needs. YOU have to test the equipment in your workflow and under your tyoical shooting conditions.
The stark reality is that it doesn't really matter which system you use. It all comes down to how you work, how much you need to crop, and the final destination for your shots.
I shoot beauty for magazine publication, not for an LCD. The differences between the Canon and Phase backs, while very apparent on an Eizo and before any post work, disapears once the files are retouched and sent to print on a crappy web press somewhere in the midwest.
Case in point: I don't own a back. I rent two or three times a month, usually a flavour of Leaf and always on someone else's dime. I was shooting on location when the A22 I rented refused to talk to my AFd (turned out the AFd was the culprit). Half hour later still no love. I finished the shoot with my 1ds2 (which I own). I processed the files and sent them to the client and then the approved shots to the retoucher (who bitched about the Canon color and abrupt high contrast tonal transitions), and what do you know, they look as good as MFDB files in print. Not as large, sure, but for a full page in a mag they look just fine.
My advice: If you are a hobbiest, have at it. You have no ROI to think about and no overhead keeping you up at night. If you intend to make money, really look at your needs. Landscape, movements, etc. MFDB (or really, film) makes some sense. Fashion, street, commercial work outside of major markets, 1ds2 will be fine. For products and beauty, MFDB is becoming the norm. But remember, you don't have to BUY a back. Rent backs on the client's dime. Even $500 editorial jobs will pay for extensive rentals.
And for all the testers out there debating whether He-Man could beat the Hulk in a cage battle underwater, at night, in zero gravity, let me tell you how most photographers test gear. First, we id a problem with whatever we are using now. For me, on a 1ds2, it was DR, flat color and tonal gradations, and the time it took to fix these problems in post or the way it made me change how I light. I rented a Sinar 54m in 2003 and shot a model test. Problems solved: plenty of shadow detail, smooth tonal transitions, amazing color. I still have these images in my book. I did not shoot a parking lot, a brick wall, my cat (yes I have a cat), a step wedge or some goof ball from my Camera Club. I test gear as if I were shooting a job, which reveals more to me than any Step Wedge shot in 1/3 stop brackets. Food for thought. Enjoy