Got the M80s.
Room size: 19x12x8
I considered bookshelves because I’m sitting close (7 feet) but decided to future proof myself with the M80s. Happy I did because the M80s allow me to feel the punch of the bass coming from the direction of the on screen explosions and such in movies. I also prefer how they sound with music over bookshelves. One problem is controlling the bass coming from them is harder do to placement constraints which wouldn’t be an issue if I was getting all my lower bass from just the subwoofer. But I feel it’s worth the tradeoff to feel the directional punch in the chest.