I'm not an expert of anime. I haven't even read the manga, which I'll do it btw. But I can assure you that attack on titan will keep you interested from the very beginning thanks to a gripping and original plot. There isn't a single boring episode, it's always suspance and action. It may seem a superficial fantasy anime but it actually deals with important topics, such as freedom. Furthermore, the soundtracks are so good that you will start feeling patriotism for an imaginary country.