There are plenty of great brands of cross trainers out there. A good pair of cross trainers will cover just about any aerobics class you do. Which brand to buy depends on your feet on how they feel with the shoe on. What works for me, may not work for you.
What are good brands to try ? Nike, Reebok, Asics, New Balance, etc... If you're concerned about fit, go to a reputable sports store and try on different brands.
Contrary to popular belief, one size does not fit all.