v4 looks the same as previous versions but they do not sound the same. They present a deep and wide soundstage with layers of images and black (quiet) space between those images. Fidelity is also much better across all frequency bands.

If your room is for movies only, v4 isn't a necessity. In fact, I'd say stick with your v3. At my place, there is no difference between M3, M5 and M100 when watching movies. Music is a completely different story.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated