Yes, not all fish foods are the same or as healthy. The first thing you look for are additives/fillers/binders like cereals, meal, etc. If the food contains fish, then it should be "whole" fish. If it does not say this, then the "fish" is likely the discarded bits that are not as nutritious.
Omega One foods are whole fish and no meals or cereals. I use their Veggie Flake for upper fish, Veggie Rounds (sinking disks) for substrate feeders, and shrimp pellets (substrate). They also have a shrimp flake.
New Life Spectrum is another quality brand, and I use their basic freshwater flake with garlic.
I know these two are quality, I have looked into them, and they are available locally at online prices so they are my basics. I do also feed Nutrafin's Max Tablets which have cereals but also chopped earthworm and the cories and loaches really go after these, so just once a week to minimize the cereals. Same for their Bug Bites.
There are other reliable brands, other members can advise, as the above are what I can get and all I use. I alternate so the fish get a different food (upper and lower feeding) three days running, then a fast day, then the Omega and NLS, and frozen treat once.