In general the more drivers and the farther apart the drivers are they are the further back you have to sit for them to integrate. Also speakers with a lot of bass may overwhelm a smell room. But remember, this is a matter of taste. I use to tease a friend that his Tannoy GRFs were the world's largest headphones as he sat right on top of these very large speakers.The advantage of using seperate subs is that you can tune to bass to fit the room more easily. FOR MOST PEOPLE monitor speakers , with or without subs, will work better in a small room but YMMV.
