Hey, how, or what parameters are we using to define 'best'? Are you asking the fish?
Is it how quickly they're dashing to the surface at feeding time? Is it if they don't spit it out at first bite???
Actually I'm wondering if what's best in terms of fish health may be different than what's best in terms of tank parameters? I.e.., surface scum, detritus and algae control???
Myself, I do use a variety of different foods. I have two reasons. One, I'm thinking that if one brand of food is short or lacking one essential nutrient than when I'm feeding the other choices hopefully my fish will get a well balanced diet. Second, although I'm sure its anthropomorphic on my part; I think my fish like variety, they'll always be wondering what's for dinner, they'll not be bored and they'll be happier!
Still, sometimes I find myself wondering if something else would be better or best? Sometimes I try to compare the ingredients on the label and if I see a lot of flours i.e., wheat or corn meal and not many seafoods (fish or crustacean meats) listed I put those back.
A few things:
Yes, I use the Tetra min crisps, it gets a pretty good rating with most of the fish.
Not all the Hikari products are free from copper, I have their Cichlid Gold Pellets, it list copper sulfate. I also remember the last time I was shopping a few of their other products had it in the ingredient list.
Recently I've been trying some of the HBH brand foods. They seemed to have a great range of ingredients. "Flake Frenzy-cichlid flakes", "African Cichlid - Attack! Pellets" (sinks fast and great for my Rams and Checkerboards who pick around the bottom, BNP loves it too), and most recently "Super Soft - Frozen Food Alternative" (they gobble this so fast I almost never see it hit the water with my own eyes!). Unfortunately they do have copper, but my tanks with the big guys have no shrimps.
Now my pickiest eater of all is my one Koi Angelfish. She'll spit out half of what everyone else will fight over! Her all time favorite is Aquarian "Bottom Feeder Shrimp Pellets". She loves them so much that she'll take them right from my fingers. (I break the pellets in half for her so she doesn't drop and loose them to the crowd.)