I've listened to the Mosaics - very nice.
I've owned the Mosaics and Fresco for nearly a year now and I enjoy them more every day. I auditioned the ATF speakers against a number of 'box' speakers - Boston VRM's, Polk, Mirage, Sonus Faber & Vienna Acoustics as well as the ML Clarity. IMHO, the electrostatic and ATF speakers outperform many of the box designs, in their ability to create a clear, crisp & open presentation, especially in the mid-to-high frequency range, without coloring (distorting, altering or otherwise degrading) the sound.
For my application, the ATF speakers were a good fit, literally (compared to the electrostatics), due to my small listening room - even the Clarity would be overpowering, visually at least (must consider the WAF).
Another advantage of the Mosaic and Fresco, being dynamic speakers is that you don't have to plug them in. This makes placement and setup somewhat easier and less-dependent on AC power and wiring quality (and quantity).
I certainly don't mean to imply that these are better than the higher-end electrostatics (I wouldn't dare, especially here), only that they offer impressive sound in a small, convenient package and at a reasonable price. They're definitely well-worth an audition for anyone shopping this price range.