The medium format digital back marketplace can be quite confusing, even for the people who are supposed to be the experts.
I think this comparison is like every other one I see on the interweb It's ok, but for some reason it's either a photo of a brick wall or a tree.
Maybe that's the perceived market, brick wall and tree photographers.
The test I would love to see is skin tones and how they react under different lighting and ambient color.
The Leaf backs I owned were less succeptable to ambient color bounce, but had an awful time with direct hard light on light caucasian skin. One hard Frensel or profoto head on those pasty white models threw up a magenta cast in the arms and legs from highlight to shadow. Maybe because the transition is so abrupt
Then again the Leaf back loved soft key like window light and would produce a beautiful look.
The P30+ I use Works well under direct lighting, really well under direct tungsten light, as long as you have a lot of watts, but it also picks up every single skin blemish, or change in color like nothing I've ever seen. I'm sure this sensitivity is great for shooting food, but sometimes it means a lot of extra post production work to paint out the the over sensitivity to color. Great news if your a retoucher, bad news if your paying for the retouching.
The Hasselblad 39 mpx back I very briefly tested probably produced the best skin tones of any medium format back I've tried. More of a Canon like skin tone, which I find nice.
The thing about medium format is none of the makers really show the true value of their files,
which is working a file deep in post. Even a 18mpx p21 file you can beat the hell out of in post and get that deep uber sharp look, especially with hard light.
The p30+ takes more abuse still and that is the one area where medium format squashes the dslrs with their AA filters.
I know dealers don't have the resources, but some db maker should show an image from start of capture though all the retouching steps to finish to illustrate how well their files hold up.
JR