I have a Canon New F-1 and a 5D MKII, and I find I use the F-1 when I want the results on film, because I like the look of film for B&W and have no interest in any kind of digital B&W prints (though in general I shoot mostly medium or large format for B&W) and I usually prefer the look of color slides and the ease of editing slides (mostly for bird photography, where a larger format or RF aren't options). I'm more likely to shoot digital when I'm shooting for someone else who needs a digital file, or for copy work where I'm essentially using the camera as a scanner, and sometimes for family photos where relatives want images right away via e-mail. Most of my lenses are interchangeable or convertable between FD and EF mount, and I own no autofocus lenses.