I forgot to mention that I carry at least one SP101 daily, virtually everywhere. It is clearly a back-up weapon, by definition, on police patrol. Off the clock, it may be the smaller weapon, or an equal as it rides with another SP101. Yes, I normally carry two handguns. A broken part, in my S&W duty sixgun, 'way back in the 1980s, has made me fairly religious about it.
Why the SP101? Well, the grip shape and angle are perfect for my hands, mitigating recoil very well, and I can get all of my skinny fingers onto the gun, making it easy to control. Small enough for quite deep concealment, yet large enough to shoot like a service revolver; what's not to like?