Craig, besides Katzmaier's reviews, check the reviews for the ST60, VT60 and ZT60 here
in Sound & Vision(now combined with Home Theater Magazine and showing improvements).
Also, in the November issue of Consumer Reports all three are recommended. The VT60 and ZT60 got the same test score of 73, and the ST60 got 72.
My view is that the VT60 and ZT60 don't appear to justify their added cost over the ST60, which is the best buy at about half the price.