It's for my son and more a fantasy piece than useable armor (the metal is fairly thin gauge, for one thing), so the decoration is going to be a mounted pair of antler spikes, one on each side.
True, but the flat top is a bit easier for this novice making his first piece of armor.
(That said, I have been tremendously annoyed at some of the helmet designs I see on "Game of Thrones". Some of them seem designed to catch blows rather then shed them, and almost all of them leave the face exposed. There was a scene in the first season where two characters joust with open-face helmets, and there are any number of times when characters go into battle without any helmets at all, even when otherwise fully armored.)