After considerable study, I had the C&S SFS kit installed in my T-series BHP that I carried as a personal weapon during Vietnam. First of all, I do not want to get into an argument over whether 'cocked-and-locked' is safe. I am simply stating that an SFS-configured pistol with its hammer flush against the slide not only looks safer, it is. Now to the nuts and bolts.
When someone draws an autoloading pistol cocked-and-locked, his/her thumb rises to grasp the safety and pull it down, rendering the pistol ready to fire all rounds single action. That is the advantage it has in the eyes of many over weapons that fire the first round double action, and the remainder single action. I agree -- this is an advantage. However, an SFS-configured pistol has exactly the same advantage. When someone draws an SFS pistol, his/her thumb rises to grasp the safety (now a hammer control) and pull it down, which flicks the hammer back into firing position, rendering the pistol ready to fire all rounds single action. In this description, I tried my best to use exactly the same language I had in describing drawing and firing a single action pistol just above, changing only what had to be. My point is this: anyone who is used to carrying cocked and locked has nothing whatever to learn when using an SFS pistol.
Except for how to field strip an SFS -- You no longer can lock the slide all the way back so as to remove the slide release/stop. This has flummixed a number of very experienced handgunners, who became convinced that in order to remove the slide stop, they had to hold the slide well back with their fingers. Two demonstrate this completely unnecessary exercise on a youtube video. Others have complained about having to do this, considering it a fatal step backward. All because FNH inexplicably did not explain a wonderful new feature of SFS Hi Powers -- which I stumbled upon. With the slide in battery, cock the hammer by flicking the safety/hammer control down; then push/pull the slide stop out to the left and ease the slide off forward. That's it! The SFS Hi Power is the easiest autoloader to field strip that I know of. Reassembly is just as easy.
If FNH had done a decent advertising job on the SFS-configured Hi Power when it first came out with it, I believe the Hi Power would still be king of the road. Unfortunately, it seems that FN would rather make assault rifles and machine guns than Hi Powers. Someone should buy the SFS configuration patents, and start making chocolate clones.
I will now tell a story. In 1916, in a Mexican border town, CAPT George Patton and his wife attended a social event. Georgie thrust a Colt 1911 into the front of his pants, certainly cocked and presumably locked. During the party, that gun went off, almost taking off the family jewels. Georgie brazoned it out (presumably without bleeding noticeably), and no one ever knew it was his gun that went off that night until his biography was written about twelve years ago. (If you want a citation for this, PM me.) Is this a slam on 'cocked-and-locked'? Gracious sakes alive, no! Could happen with a Glock! In fact, I think it did recently.
Cordially, Jack
