Grischa, it's all been about workflow efficiency on set. Having a really workable Live View has made work much more enjoyable. I'm able to achieve critical focus more quickly. I can compose more accurately. Also, when the designers and art directors I work with are working on propping, they immediately transitioned to just walking over and looking at the back of the camera instead of waiting for me to grab a new capture for every adjustment.
The image quality is not on par with my IQ 260, but then, I bracket and composite for every shot I do, and after 6 months of shooting strictly on the Sony, I've seen no loss in image quality with my deliverables.
I didn't use the HR 40, but rather the SK 43mm XL. The Blad 40 actually allows greater movements with the Sony. This is due to it's greater rear focal distance, as the camera body begins to vignette the image circle of the Schneider at around 20mm of shift. I've never really used more than 12mm of shift on that lens anyway, so I have way more movements available to me than I need. Also, because of my workflow, I never stitch images.
For wider shots I use the Canon 17 and 24. I'm having a Canon lens board made, so that I can use those on the new Arca and have better movements than what are available on the lenses themselves.
I've almost bought that Contax a few times now... I'm on the fence though and considering the Pentax as well.
Cheers,
CB