The four most recommended brands on lots of hamster forums are Oxbow, Hazel Hamster, Mazuri, and if you can't find any of those, then Carefresh Complete is alright.
Oxbow and Mazuri are both pellets, so hamsters obviously like them less than they would Hazel Hamster, which is a seed mix. Seed mixes provide variety, and keep the hamster from getting bored. I personally feed a mix of Oxbow and Hazel Hamster, and Hazel Hamster is great! As long as your hamster eats everything in it and doesn't pick out the parts they like best, I would go for Hazel Hamster.
But since you have Dwarfs,if you decide with a seed mix, you have to remove the corn (both whole and the flattened ones) and peas because they are high in sugar, and too much sugar in a hamsters diet causes diabetes. Also, remember to only feed 2-3 sunflower seeds a day- their oils are essential, but fatty, so they can only be fed in small amounts.