Interesting,
I have used the IQ160, 250, 150 and 3100, and to me the LCD's all pretty much are the same in how they handle. I have always assumed that P1 is using the same LCD between all of them.
As some have pointed out, the time it takes to zoom to 100% can be time consuming. And once zoomed it may take a few seconds to refocus if you move around with your finger. But again, this is the way it's always been so I am I guess used to it. But it's also a reason I will attempt to tether in the field when I can as the Surface pro and C1 solution is much faster. As for focus with Live View, once zoomed to 100% I usually have no problems, with the XF very easy to determine what is in focus. However the Acra rm3di makes things a bit harder since it has such a micro control on focus it can be hard to determine the best focus. But that is not due to the LCD, at least to me. The IQ screen does allow you to control the brightness of the display on Liveview which can help a lot in lower light.
I have also use the Nikon D800, D810, etc and it's easy to zoom in to far on those cameras, I have always dialed into 100%, then backed off 3 steps to get the best focus. I would love to see focus peaking the Nikon and Phase as I have it on the Pentax K1 and love it.
I was happy to see the comments Bernard made on the Hasselblad 100, as it appears to handle both the Liveview and zoom feature quite well, and it sounds like the process is much faster than P1 especially the zoom. But where P1 to me is the slowest is when previewing a captured shot on the LCD, where it can take several seconds to get the image zoomed up to 100%. Many times you will get a overpixelated like 400% view and you have to back off to normal and start again.
Paul Caldwell