FWIW, I thought that a SOB holster would be usefull for deep cover carry of my S&W 640-1. Fortunately, the model that I bought (Don Hume DAH) includes a provision for strong-side hip carry too.
While it (SOB carry) looked good in theory, I found several problems that make it unworkable for my personal CCW needs.
I'm fairly large (6' 1 1/2", 215 lbs.), and my arms aren't short (34-35" sleeve on dress shirts). With the way that the holster is designed to position the butt (think of a conventional hip rig rotated about 80 degrees from vertical) it's impossible for me to draw the weapon with a firm firing grip unless it is positioned just behind my hipbone. When it's in the true "small" of my back, I can't even grasp the revolver without some major contortions. Slow, awkward, and totally impractical for me. If the grip was positioned with the butt pointed "down" instead of "up", it'd work much better.
It's also extremely uncomfortable and makes the weapon inaccessable when driving. Strike two.
Should I be knocked down in the course of an assault, I'd likely be SOL. It'd be tough to get to in almost any situation that I can imagine, and darn near impossible if I were supine. Especially while being pummeled by someone sitting on me. Strike three.
There may well be other SOB designs where these are lesser issues, but virtually all of the ones that I've seen pictures of position the weapon in much the same manner.
I realize that generalizing from the experience with one design doesn't preclude the concept from being usefull to other folks. Personally, I don't have the resources to buy forty-eleven different holsters in search of one that'll make this mode of carry work for me. When I compare my needs with the various other carry options , the several practical disadvantages of this one outweigh the theoretical advantage.
YMMV
