Hmmm...in my opinion, here are some important factors to consider, so I'll address what I think is important without gettnig too much into the pros/cons. I'm sure there will be plenty of diverse opinions on this, but here goes:
1. Whatever you decide to carry for personal defense, you should use in your practice/target shooting.
2. Whatever you decide to carry for personal defense, you should make sure will function reliably in your gun.
3. In general, for a given velocity a heaver bullet (of the same design) will penetrate deeper than a lighter bullet.
4. Higher velocity in a lighter bullet does NOT directly equate to equal end performance between lighter and heavier bullets. Just because you have the same calculated energies does not mean the same terminal ballistics at the target.
THAT SAID:
Everything is a trade-off and there are endless debates/arguments on what constitutes "the best".
THERE IS NO "BEST". There may be a "best for (fill in the blank) circumstance, but change one thing and that goes out the window.
If I may quote Frank Ettin in another posting:
“So as a rule of thumb:
More holes are better than fewer holes.
Larger holes are better than smaller holes.
Holes in the right places are better than holes in the wrong places.
Holes that are deep enough are better than holes that aren't.
There are no magic bullets.
There are no guarantees.”
On a personal note, I typically shoot 115 gr. Winchester Whitebox 9mm in my Beretta 92FS. For self defense with this gun, I carry 115 gr. Speer Gold Dots.
They have the same bullet mass, virtually the same velocity out of my gun, and they are indistinguishable in reliability and accuracy/point of impact for me. Therefore I get the benefit of being able to use the more inexpensive WWB ammunition for target practice while being comfortable in knowing that my self defense rounds will hit where I am aiming, just like my practice ammo.
Pick what suits you based on these factors and practice putting them where you want them...because regardless of their performance characteristics, they ain't gonna perform well against your target if you can't hit your target.