I have both. Originally, I got the snubbier versions, for ankle and pocket carry, for back-up guns. More recently, as I near retirement from policin', I wanted a good belt holster gun, and saw the extra barrel length as a benefit, offering more sight radius, and a bit more weight on the end of the barrel. (I currently carry my personally-owned duty P229 pistols concealed on my own time, but after the badge goes on a plaque or into a shadowbox, the oath to intervene on behalf of others 24/7 will no longer be in effect.)
I wish I could buy a 4" SP101 in .357 Magnum! I did buy one in .32 H&R, when they were still available new.
Oh, and BTW, all SP101s have hammers. Not all of them have spurs on the hammers.