Cards and discs are old technology now, most all of todays embroidery machines use USB flash drives. What brand to buy is a personal decision, you're likely to get as many opinions as there are machines. And your budget will play an important part in your decision. I'm partial to Janome and Brother, though I'm really sold on Janome for embroidery. The Janome 500e is my favorite of all 5 of my embroidery machines. It's an expensive machine but oh, so worth it.
Cari