To be honest, I don't think it really matters. Where most aquarists go wrong is to buy big tubs and use them up over a year or so. The problem with this is the "shelf life" once opened -- some of the essential nutrients oxidise, and the nutrional value declines as a result. So after a few months the fish can eat all the flake they want, but still be starved of certain specific nutrients. I throw away any pot of feed more than 3-4 months old.
If you want to buy in bulk, then perhaps the thing to do is to divide a big pot into small tubs, and then freeze or otherwise store the smaller tubs until you needed them. But that's a bit of a hassle given how cheap flake is. I just buy a small tub as and when I need it. Often I'll use on brand one time, then another the next, and so on, so that my fish get some variety.
Personally, I've found the Interpet flake to be accepted by even somewhat tricky species such as halfbeaks and wild danios. Colour enhancing food, for whatever reason, never seems so popular. Those trout pellets sold as catfish food (and their floating mini-pellet equivalents) may be cheap but they seem the least popular of them all. I do worry a bit about their high protein levels. On the other hand, the Hikari products all seem very readily taken, and when I kept cichlids of various types, Cichlid Gold seemed to be accepted by most.
So basically, get a small pot of whatever is to hand in your local store, and see how it goes. I think aquarists over-worry about feeding their fish. Flake food has been around for decades, and the manufacturers are pretty good now and producing stuff that is optimised for the health of tropical fish. Alternate with frozen bloodworm, and use live foods as treats when you have time to sit and watch your fish, and you're in business!
Cheers,
Neale
Is there a particular type/brand of food you would recommend?