The J frames are about the perfect ankle carry guns if there is such a thing. I don't find them comfortable either IWB or pocket due to the width of the cylinder and length of the muzzle to butt. My 637 carries on the ankle like it was made for it. The only thing I don't like is for some inexplicable reason Desantis did not give the J frame version a standard thumb break like the autos get, just a cheapo nylon strap that velcroes to the body of the holster. What I do is only attach the velcro about half way so that I can just pull the gun straight out without undoing anything. The Apache hugs this gun so closely you could probably just dispense with the strap altogether.
My 637 is loaded with a 146 grain lead semi-wadcutter at 760 fps: respectable performance for a gun this size, accurate, and easy to shoot.