This is a low key classic. A relatively simple but emotive art style, a continuous and natural shift in tone from beginning to end. What starts out as a potentially average harem comedy quickly turns into shonen battle manga/sci-fi-fantasy without losing the harem comedy element. Snappy writing, a large cast with interesting characters and a sense of fun throughout.
This story has a happy and satisfying ending. And the spin-off, UQ Holder does a good job of bookending the Springfield family legacy. Hats off to Ken Akamats-sensei.