Unlike baking a pie, I don't think there is a wrong apple to use when it comes to making candied apples. I believe that Granny Smith apples are usually used to balance out the tartness of the apples with the sweetness of the caramel, and toppings. However, if you prefer Honey Crisp, Galla, Fuji, or my personal favorite, Pink Ladies, go for it!  There are no "gourmet caramel apple police" the last time I checked!