I think he's right about most people don't actually do a comparison. I live in Virginia where everyone and their grandmothers carry and a lot of guys tell me "oh you need a 380 or 9mm single stack". At the end of the day it needs to be a comfort for you, not someone else.
With that being said, I'm a big guy. I have bear like paws so honestly for me a single stack 9mm feels too small. I tried to carry my wife's Sig 380 but I wasn't comfortable with it. Since I got my CWP I've been carrying a Mod 2 40 s&w 3" Sub. I've since started carrying the 4" Service Mod 2 in 45acp for 2 reasons, One I shoot really well with it and two it has 13 round mags.
At the end of the day it works across the board, for me. I can hide it very well and if I need extra concealment I'll grab my 40 or LC9s.
I know this concept won't work for everyone and I get that. 2 things I've learned in my time of carrying is that if you are going to protect yourself you better be well adapted to your weapon of choice and have sufficent ammo. Shot placement is #1 but I worry about multiple attackers.