Yes, the split image screens always made me unnerved - both plain and 45 degree verisons. I know plenty of people who feel right the same about them. I am so glad my Spotmatic does have a simple microprism screen... and I've never seen any studio photographer here with anything but a plain matte screen with center spot (designed for macro and close-ups) in their Hassies and Mamiyas RB/RZ. The halves and stuff around make it just impossible to see model's face, and they are often the reason for a badly composed in a hurry images with face (the focus was set on it, right?) in the very center of frame! Rangefinders is another thing - but as for reflex cameras, my heart is with plain matte.

Cheers, Zhenya