If I remember rightly (happens now and then) 2 of my SD cards come from 7DayShop, they're "Viking" ones (a 1/2 Gig and a 1Gig).
I've had no problems with movies (standard and re-sized ones), MP3s, Txts or Games , they all run off either of the cards.
Hope that helps.
Edit: Grammar sucked, edited!