I use a H3Dll 39Mp MS, almost exclusively in 4 shot mode. I love it and that's all that matters.
It doesn't matter a damn "if mine is bigger than yours". All that matters is that mine does exactly what *I* want it to do.
If you are trying to earn a living from photography, surely it matters if you customers are happy with the results and prepared to pay for them?
99.9% of professional work is reproduced at A4 or smaller.
I think that many of us here target that .1 % of the market - partly as anyone can do much of the 99.9% "adequately" with a sub £500 camera.
This site is tradionally peopled by obsessive, pixel peeping, landscape shooters and this thread (accepting that there are many pros and dealers contributing) is typical of that mentality.
I admit to being an obsessive IQ conscious landscape shooter... does that make me mental?
If you are not IQ conscious, why do you use a 40Mpx back in 4 shot mode?
Multi-shot blows away single shot pixel for pixel. So, the only relevant comparison, in my opinion, would be single shot vs. single shot using the *same* lens, as someone correctly suggests above.
Are you comparing to MFD single-shot or Canikon AA work?
4 shot might be OK for studio, but for landscapes with thing moving, a 60 Mpx MFDVC is better, with or without shift-and-stitch.
When I get my H4D-60, I will invite P65+ users to come to Warwickshire so that we can use different backs on the same view camera with apo-digitars.