I don't own one, but I've seen them in person a couple of places.
Impressions: very nice. It looks very cool and i like the sleek black acrylic stand. I don't like that the size I would want is relatively short, but I guess this is necessary so that water doesn't do too much splashing.
I worry about the noise level, and b/c I saw them at LFS's with a lot of background noise I couldnt tell what they would be like in a home. The LFS salesman commented that (obviously) the tank has to be perfectly level or else the overflow doesnt work (or at least look like its working) properly, and a larger than average return pump is needed for the tank size.