I just picked one of these up and was very pleased with the initial impressions. I am not a warm sleeper by any stretch of the imagination, but was comfortable at about 20* with some help (bivy, heavy long johns, and light hooded down jacket). It also seems to be lofting well past the 2" of single-layer loft usually associated with the 30* temp rating.
Considering the price, it's probably worth at least giving it an in-person look.
That said, I certainly wouldn't discount the opinion in the above post, since that's not the first time I've heard these complaints about it- these could easily be reasonably inconsistent in their manufacturing.
Edit: Forgot to add that I only have one night of testing this quilt, and thus the above shouldn't be taken as any sort of long-term commentary on the Z30.