My guy turns his nose up at Aqueon and prefers Omega One. I'm a beginner myself, but looking at the jars side by side Aqueon has more fat and fiber and less protein by comparison. Its second ingredient is wheat flour, versus wheat flour being the fourth ingredient in the Omega One food. Since bettas are carnivores, having a lot of flour in it makes Aqueon look...less than impressive. It's like instant ramen instead of beef stew.
If you've got a juvenile, I'd go for whatever packs the most protein. He'll need it to grow. I got my .61 oz jar of Omega One for about four dollars at the local pet shop. More expensive than Aqueon, but not too bad. You could always keep the Aqueon around for emergencies.