That system was designed a single room. No problem to scatter them over entire house as each of them presents itself as an UPnP renderer and all of them can be controlled from the single point such as, for example, tablet running BubbleUPnP app.That would probably give you more stability at the expense of range. Not a bad tradeoff if you aren't scattering them over the entire house.
If they're better at filtering out line noise then there will plenty of room for these to grow before they run into interference on their own transmission frequencies since they aren't very popular.
They don't do fitlering, they actually got better in modulation technique which gives them more speed and better resistance to line noise.