My Betta absolutely loves these things. I've had no problems with them whatsoever and I don't find them to sink immediately. I especially like that they don't all pour out at once so it's quite easy to portion the food.
I have multiple betta fish and have had some mixed responses to this food. All of my fish will eat this food however the pellets are much smaller and tend to sink a lot faster than some other foods. This makes it difficult if you have a betta that takes it's time eating and only wants to find floating food. This is a food I will use in rotation but won't be a main diet for my fish.