I chose .40 over .357 sig because of bullet selection, availability and reduced cost vs. .357.
DoubleTap .135 grain does 1310fps (515 ft/lbs) -1420 (605 ft/lbs)fps- depending on barrel length) basically mimicking .357 Sig or 9mm +p+.
You can go up to 200 grain bullets.
I have a mix of 135 powerball, all the way up to 180 gr Remington Golden Saber ammo. I lean towards the 155&165 Federal HST.
Originally, I was really interested in .357 sig, but after looking at the additional cost and huge bullet selection of .40 S&W- in my mind there was no reason for .357 sig. I also prefer .40 over .9mm because of the great variety of bullets weights. 10mm is even better in this regard then .40, but since I am not a reloader, it's cost prohibitive for me to use 10mm.