Are you thinking of hand holding as in no tripod? If that is the case a RF with a wide fast lens is the only way to go. Range finder because mirror slap on an slr is going to require a shutter speed of at least 1/15 and more likely faster. With practice shooting handheld at 1/8 w/o support is very doable slower speeds when leaning against walls poll etc.. A wide angle lens because camera shake is less noticable or likely and DOF is greater at wider apertures. A fast lens because... well thats self evident.
I'd go with the Bessa.