Wiiig.
Spray is horrible.
It's sticky, you can't really touch or style your hair once it's in, some have a strong and I mean strong hair spray odor that doesn't go away till it's washed out.
It stains your scalp, your clothes, and not to mention the area where you're spraying it, you don't want to stain the hotel.
Also, if you sweat, it'll run off and stain your cosplay.