It does work in a little romance, and a little humor, but it doesn't sit heavily over one genre line. It is also refreshingly free of the ecchi content that so frequently sours other shows.
I'm not saying that "it's fun... caveat, caveat, caveat", like you might expect. It is pure fun. Where most shows fail, this one balances all its elements perfectly, with an elegance to this purity of fun that can have me saying only one thing: Give me more!
