Okie, I think a lot of the .40 issue has to do with the packages they're offered in....like the very small compacts and subcompacts, and the fact that they keep trying to stretch the .40 velocity #s into the realm of what the 10mm was originally moved away from over....which can make the recoil in the smaller guns pretty evil for smaller or less experienced shooters...or everyone, regardless. I had two Springfield P9s, years ago (CZ clones). They were the compact model. The first was in 9mm, and it was great. I got the .40 when it came out, and that thing would bite you at the beavertail, no matter what you did, to the point of drawing blood after a couple of mags, unless you wore heavy gloves. I could shoot it great....but it obviously was not as 'fun' as the 9mm version, in the same pistol, due to the (obviously) snappier recoil and short beavertail. 45s don't seem to have this problem, either. I own and have owned plenty of 40s and 10mms, and like them all...but the +p 40s in smaller guns and full house 10mms are different animals for follow ups. Interestingly, it's not nearly as noticeable to me in 357 sig, with regards to flip/recovery/doubles/etc. ...but I haven't tried it in anything smaller than a Sig 229, either. If practice ammo cost isn't an issue, then the 357n Sig is another auto caliber to consider....the bullet size arguments will go on forever, but I don't think there is much arguing the dramatic effect 115/124/125 grain 357/9mm bullets (or 135-165gr 10mms, either) moving in the 1400-1600fps range have shown. There is something magical about most handgun bullets when they get to 1400 fps and up that seems to magnify effect over the 850-1350 stuff, regardless of caliber/weight....whether that relates to the velocity itself or transfer, etc. I'll leave up to the scientists/ballistics experts...I've seen it on animals, vs. what I always thought was the 'ideal' in a .45 185-240 JHP at 900-1050.