It'd be interesting to know which picture mode WHF reviewers used. (Perhaps several, though I'm guessing "Normal," as this seems to be WHF's favourite preset when testing Panasonic plasma TVs.)
Of course if the TV was tested using the EBU preset, everything the review said holds true. Switching to another preset would have revealed contrast and brightness performance on par with the VT65 (though not quite on par with the GT60). However, measured ANSI contrast, as reported in several reviews, is almost identical across models, though the ZT65 edges it in terms of MLL.
In my view, all these points are moot, since all of the abovementioned televisions produce brighter images than enthusiasts would ever want; and let's face it, the ZT65 is aimed squarely at the enthusiast market. The overwhelming majority of ZT65 owners will get the TV professionally calibrated (or perform advanced user calibration), and will situate the TV in an appropriate, light controlled environment.
I'm not basing what I say on review data, either. I've seen the TVs side-by-side, fully calibrated, and brightness and contrast levels looked identical.
The "too expensive for little gain" argument is valid. Individual consumers will have to decide if it's worth paying the extra; many have concluded that it's not. I'm not so sure about the "not bright or punchy enough" claim, however.