I have not heard much, but so far I have heard fairly good things.
I do not know, I rather spend more on a floating deck hydro Exmark, Toro, or Gravely, they just seem like a better built mower to me. I love Scag's Zero Turns and fixed deck walk behinds, but the new SWZT just looks a little cheap. A lack of a 52 or 60 inch deck option also disappoints me. I also await to see the new Bobcat Floating Deck Hydro.
That said, if Scag were to bring bring back the SWZU, I would be all over it. A friend of mine has one and it is a tank.