I agree DOF is a learning curve with MF. I recently bought mamiya 645J, and whilst I am really pleased with it (and I do carry it around on a neckstrap with a prism finder), I have found several shots where I was surprised I had missed the focus. With 35mm at 5.6 and beyond I don't find DOF a great issue - provided the subject is in focus, the rest fall around it OK. With MF, this doesn't work and you certainly have to start spending more time on focussing.