Big Maggies and other line-source-approximating speakers have an interesting characteristic: The sound pressure level falls off more slowly with distance than from a point-source-approximating loudspeaker. So they lend themselves to larger rooms better than you might expect, in that the increase in power needed to "fill" a large room vs a smaller one is a lot less than the increase that would be needed for conventional speakers.
Also, in my experience Maggies and such really bloom when you can give them 5-7 feet between them and the wall behind them. This allows a nice long time delay before the additional (spectrally-correct) reverberant energy from the backwave reaches the listening area. Imo dipoles (and bipoles) are at their best in large rooms.
Dipole bass is often better in large rooms, where the out-of-phase backwave isn't reflected back towards the listener as quickly. That being said, dipole bass generally doesn't have the chest-thumping impact of a good box speaker because it doesn't actually pressurize the room. But in general dipole bass is smoother in-room than bass from box speakers, so the subjective speed is better (smooth bass = "fast" bass), and the pitch definition is also usually better.
Duke
dealer (of dipoles)/manufacturer (of bipoles)/longtime Maggie fan (I've owned five pairs)