When you take the water out of the different kinds of foods, the po4, protein, etc all end up being about the same, or roughly the same. If you don't rinse frozen food, then the "juice" can add things that you don't really need unless you have NPS and dry food can be a bit better. Pellets are a great way to get lots of protein, fatty acids and vitamins to fish that are harder to get in frozen foods unless you feed a large variety including brains, guts, etc. If you think of phosphate as a building block, it is there in relatively equal amounts in all food that can also be used to build tissue, so if your po4 stays low with frozen, your fish are also getting less of protein, fat, etc. too and lots of water.
Brine Shrimp Direct is underrated, IMO. Their Caribbean mix and mysis by the kilo are a staple at my house. NLS is still my go-to pellet although when I use my the 10 pounds that I have left, I might look at some others. Spirulina in flakes are far superior to Nori, IMO, although this is just based on my own experiences and anecdotes. I love this place.