Bookshelves+stands and floorstanders typically have the same footprint. When a dude's claiming he saved space, he did not ( it was just psychological for the dude). Unless you're stuck with nearfield listening distances (where drivers don't have room to sum) or budget constraints, don't bother with dinky lil bookshelves.
When a manufacturer offers both floorstanders and bookshelves, typically the engineer's maximum time and devotion goes to the floorstander (the bookshelf's the dinky lil afterthought). Always go with the floorstander when possible.