I've recently added an F3 to the F100 for 35 film shooting. What a nice thing it is to have the split. I have three screens with it including the B and E screens which are with no focus aids. It is still much easier with those as they are coarser and the image snaps in a bit. The F100's screen is my one great frustration with MF glass. It is really hard for me - more of a guess really, every time.
The clear and bright screens on autofocus bodies is necessary. The focus array is on top of the prism housing and so light has to pass through the screen to reach them. The brighter and without texture they the screens are the better the autofocus works. Nice for autofocus - but a real step back in versatility.