I am a big fan of the 45 and never did well with the 21 as it just felt too big for my hands. I just purchsed a 21SF. While the difference in grip size isn't much it just may be enough. I haven't got to shoot it yet but I notice I can drop the mag with my trigger finger now that it has an ambi safety without moving my hand and disturbing my shooting grip. If I drop the mag with the thumb of my shooting hand I have to change my grip to do it. Mine has the pic rail. I hope it will shoot close to my Kimber CDP pro as far as accuracy but that would be doing pretty good. I'll let you know.