We went to the Mosaic because it was much cheaper than any other decent-sounding hotel in the area. We weren't disappointed. It's a lot like a Kimpton, maybe a bit less fancy and somewhat smaller rooms. High points were the friendly, supportive staff (one of our suitcases was lost so we needed them for various things), and the fact that they had a hotel car and driver to take you around the neighborhood for free. Lowlights were that the room was a bit small (though attractive and well thought out) and that it was noisy from some machinery. I'll stay there again next time I'm in Beverly Hills, unless I'm really splurging - but I'd avoid room 214 for the noise. It was about $300 for a room. By comparison, our event was 12 blocks away at the Montage, and the cheapest room there was $600.
My two suggestions to them are 1) do something about the noise in the room, and 2) leave the shutters open. There was a nice little view into the pool area, but between the opaque wooden shutters and a sort of ornamental drape arrangement, I just assumed that it backed onto a wall or something and never opened them till just before we left.