SnowySurface: The Small fish formula is actually better because it has higher protien. Plus I think that the smaller pellets are easier to digest. :)
IMHO, asking what the best pellet is probably won't yield very accurate results. Hikari used to be one of the best foods on the market, but they changed the formula. Unfortunately, people keep buying it because they have such a good reputation.
Good foods are based solely on ingredients, which is why there are some that are scientifically proven to be better than others based on the dietary needs of bettas. Feeding your betta food that has a first ingredient that is wheat is like feeding a cat a vegetarian diet. Their bodies are just not set up to digest greens. It is probably why a lot of bettas have bloat problems. That and freeze dried bloodworms...