I actually switched all 4 of my guys from Zupreem Natural pellets, which they were on for years, to Tropican pellets and Tropimix seed-mix about a year ago, at the suggestion of my Certified Avian Vet, who actually has a Blue and Gold Macaw who he feeds both Tropican pellets and Tropimix seed-mix to! The Tropican pellets are much healthier overall than the Zupreem Natural pellets, which contain several preservatives that have come to be known as harmful over time, which is why I made the switch...
There are several great pellet brands, the best being Harrison's and Tops, but if your Macaw likes the Tropican pellets, then there is no reason at all to switch him, as they are every bit as good for him...And the nice thing about Tropican is that if you do want to add a healthy, low-fat, non-sunflower seed, non-peanut or nuts of any kind, non-corn seed-mix to his diet, even as a "treat", their Tropimix seed-mix not only fits all of these, but it also contains the same Tropican pellets! So that your bird actually gets the same Tropican pellets when he's eating his seed-mix! I am one who feeds my birds a healthy pellet as their daily "staple" diet, but still feed them each a small amount of healthy, low fat, varied seed-mix every day too, and the Tropimix is awesome! And they all love both the Tropican pellets and the Tropimix seed-mix, even though it contains no sunflower seeds, nuts, corn, etc. And then of course they get fresh veggies/chop every day, and a small amount of fresh fruit 4-5 days a week (lots of sugar in all types of fruit, so have to limit it a bit)...But again, if your Macaw likes the Tropican, I highly recommend just keeping him on it, as it's a great pellet, and I've actually noticed a change in their energy levels, their feather health, and they've all increased their weight slightly, which they needed to do for whatever reason..My CAV does a Wellness Exam once a year that includes blood-work, and none of them have ever suffered from any Nutritional Deficiencies or any issues at all, but they were all slightly underweight for the longest time while eating the Zupreem Natural pellets and also Higgin's VitaPrima California Blend seed-mix...After a year of being on the Tropican pellets and the Tropimix seed-mix, all 4 of them have filled-out and look wonderful, and have noticeable rises in their energy levels...And I would have never switched onto the Tropican/Tropimix if my CAV had not suggested it...