Ted Nugent loves the 10MM! Depending on what you think about him, that could be good or bad!
As has already been stated, you won't normally be able to find "full power" 10mm loads on store shelves.
I was at the range with my S&W1006 shooting store bought rounds & they were actually 5fps SLOWER than
my .40 I was shooting also.....guy just happened to have a chronograph at the range & let me test them.
I was able to pick up some full power Double-Tap 10mm online & there was a HUGE difference!
I could see there would be a problem (for me) with a follow up shot with the full power ammo, but
you sure knew you were shooting something, lol.
That's all I have to say about that......
A single round out of any normal handgun is not going to put someone down without the following:
1) Them giving up.
2) Blood loss.
3) Central nervous damage.
The difference between a 9mm and a .45 in terms of wounding is so negligible it's funny to read people arguing about it. A single shot from a .223 contains twice the energy of a .45 yet they won't knock someone to the floor and immediately put them out of the fight without shot placement.
There's no such thing as a magic bullet, and proponents of the single bullet theory can't seem to buy this. Go ask any LEO, SEAL, SF, etc. what wins in a gun-fight. It's skill and mindset before equipment.
You see the same mentality in hunting. People think they need a .300 Win Mag to kill a 120 lb. deer, LOL. Fact is, they are focusing so hard on their equipment that they don't see the real reason why the animals keep running.
That's not going to stop me from owning a Delta Elite in 10mm though :P
Because the only major on-target difference between handgun calibers is penetration. A .357 magnum isn't any more effective than a good .38 +P, it just has more energy left after it exits the bad guy. Handgun power levels are hardly worth measuring when you're talking major defensive calibers, because in a defensive situation there isn't enough difference to matter. And no major defensive caliber is going to make the kind of energy (more properly velocity) needed to do more than poke a hole through the bad guy. And once the power level get to the point that your choice can punch a hole through (and not just "into"), that's enough and more isn't going to help.
So let me be a little more precise. For defense against human aggressors, 10mm is equal in effectiveness (as well as such a thing can be measured) to 9mm, .40 and .45.
To answer the other part of your question, 10mm is better for larger critters because of the extra power giving you superior penetration. If you can't reach the good stuff, it's hardly worth pulling the trigger. Less powerful calibers are going to have trouble reaching so deep in heavier, thicker-skinned animals.
Anecdotal experience is actually pretty worthless. Anecdotes are "this one time..." I'll take properly collected statistics (which are "out of 1000 times,..."), even though those aren't too much of a help. More useful is knowing how things work. How handgun bullets act on target, the way they wound, the differences in wound profiles between them... There isn't a whole lot of difference between wound the wound profiles of everything from .38 special up to 10mm. Even .380 is right on the verge of what I'd consider a major player today with a wound profile that's often hard to distinguish from the others.
As far as everybody favoring heavier bullets and higher caliber weapons, I disagree. I know ex-military who will take an M16 or M4 in .223 on a movement to contact over a .30 cal battle rifle any day. They can carry more ammo, they can put more hits on target faster, and it's plenty effective on target. I also know that a lot of spec ops types who get to fill their holster with whatever they want happily choose 9mm pistols.
If I have one shot and have to make it count? I'd like to have a rifle, please. If I have a pistol to use that way, I'll take whatever I shoot best with at the moment. Right now I'm going to say that while my P220 is my go-to handgun because it fits me like a glove, I wouldn't feel any hesitation picking up my Rossi .38 that I shoot nearly as well. The caliber has nothing to do with my choice, it's entirely how well I handle the weapon in question.
Because I know the truth. I know that 10mm doesn't do a significantly higher amount of damage on target than any other typical defensive caliber.
Why are you better off with them? Because you shoot them better? Because that's the main consideration in choosing a defensive pistol, not caliber.
After all this, I will say that I've heard that VLTOR is going to come out with a version of the Bren Ten... and I want one. It'd be a great all-around gun for self defense at home and backpacking in cat country.
"Anecdotal experience is actually pretty worthless". I just wanted to repeat that for the reading pleasure of every LEO, military member, or home defender who stared down the business end of life-threatening weapon and survived, so they would know that their real-world experiences, and the lessons they learned and shared in the process, according to you, are of no value whatsoever, and that all the expertise you've gleaned from reading up on ballistic gelatin testing and penetration levels is far superior to theirs when determining how to handle a life-or-death situation.
If I'm coming across as condescending, I'm sorry. That's not my intention at all. It's hard to convey tone over the internet.
Some raw data. Enjoy:Interpretation of FBI gelatin tests
I will concede this, however: After reading a bunch of the ballistic gel test data and interpretations, a "soft tissue" hit with a .45 or 10mm, under pristine conditions and through relatively light clothing, even though they hit harder, make bigger holes, and generally speaking have better expansion characteristics than a 9mm, seem to be only marginally more effective in terms of permanent tissue damage. So, the next time the North TX weather is temperate and not terribly humid, there's no wind or precipitation of any sort, and I'm certain that my assailant is wearing a T-shirt and will stand perfectly still and not return fire while I shoot him in the gut, I'll happily pack one of my 9mm's!
First lesson you learn about shooting real living objects ... ballistics testing is largely bullshit.