Just my opinion, but I personally feel that most proper SD ammo is pretty good.
I carry Winchester Ranger 230 gr. in my CCO. Great reputation, decent value.
The problem with "the very best" is that it boils down to someone's opinion. You may think that Brand X super tactical ultra gnarly HPs are the best. On the other hand, I might think that brand Z's Ultra Vicious Nifty Keen HPs are better. One guys Ballistic gel tests may vary from another guy's tests. Now what?
Proven, good quality SD ammo that feeds in your gun will do fine. Much beyond that it becomes a hair-splitting urination distance contest.