I prefer Froslass. Personally find Glalie sort of... creepy, you know? :( It doesn't have a body besides only a head, and its eyes are pretty vicious-looking. Froslass, on the other hand, is nothing like that. Plus, thanks to its Speed, this Pokémon could also be more useful when battling. Glalie isn't too bad, but it winds up getting taken down easily; I've used it before, haha.