Effectiveness
This is the big one, of course. Many of the "big names" in the gunzine world disparage the 9mm right and left because, they claim, it lacks "knockdown power" or "stopping power" or whatever they're calling it this month.
I won't lie to you. They're right. The average 9mm load probably isn't as effective as a defensive round as the average .40S&W, .45ACP, 357SIG, or 10mm round.
Whoa, hold on a minute! Did he just say the 9mm isn't as good as those others?
No. I said that the average load wasn't as good. When you start to look at the best loads in each caliber, you begin to see that they're almost identical in terminal performance (ability to penetrate, expand, and otherwise wound a violent threat).