to the H3D39: I had never had problems with the filter, never get this helos, I worked also with mixed light, strong light in the night ...
I saw it on a comparision between H3D39 and phase one 45 ( same kodak chip) on web, but never see it on my back.
I had other problem before: the white calibration was very bad- with hard magenta cast. I worked always with manual calibration-than the colors were good.
This year I send the camera to hasselblad and they changed the mainboard and the white calibration unit: costs about 3000 euro.
now the calibration is perfect, even the reds in skin-faces.
I have also Leaf 12 but for some works I prefer still the H3D. I like the contrast and colors of it, H3D50 seems to be more soft for me (very little)- I rented it once.
I think when money is not the important case so the newer sensor will be always the best way, but if price is important the H3D, H3dII is absolutly the best choise and I doubt it very much if on the print there will be any difference between H3D39 and H3D50. The quality of the lens, the way of using light and photo-technik will make the difference but not the chip.