The 10mm is a great round. I have a Glock 29. Thou its a much better woods round than a personal defense round.
When I look at rounds I think about knockdown or killing power.
Knockdown power is simply the energy transfer from the bullet to the object being shot.
Killing power is the damage potential to the object.
A 10mm has killing power, it is powerful and will deeply penetrate and do lots of damage. This is good for animal with thick hides, large bones, etc. . Its not the best for people because we are very thin skinned and a 10mm will likely go clean thru the person. While this does lots of damage there is not nearly as much energy transfer. The only energy lost was the energy required to break thru the skin, organs, or any bones.
A . 45ACP has knockdown power, its a slow moving heavy slug that will generally stop in its target very quickly. This isn't as good on say a bear, but great on a person. Every last ft/lb of energy is dispelled into the person, this stops them much faster than a large hole...
So. . if your purely looking for a personal defense gun against people I would look at a . 45ACP or a 40 S&W. If you want the most power in a conventional auto pistol get a 10mm.
I have both a 10mm and a . 45ACP. They are both great guns. The 10mm is my truck gun as I am more likely to encounter something other than a person and the . 45ACP is my house gun as I don't expect a bear to break into my house.
The 10mm is also quite large to conceal, so I carry a Kel-Tec . 380 when I need something concealable.