In the UK for example, the price difference between the Sony VW500 and JVC RS57 (X700) is only 1500 dollars!
However, the bad reports about 3D with the VW500 may actually mean for the first time that the JVC is better or at least equal in terms of 3D performance.
The fact that the Sony has more pop may have something to do with the position of the iris in the optic assembly. JVC's dynamic aperture still puts the front aperture in the same position as it has always been. This means as it opens more, the intra-scene native contrast reduces. Arguably, it may be better to restrict the aperture (using the manual offset), so that you don't go into retina burning territory because as you do so, you are more likely to get bright but flatter images. I would suspect that having the manual aperture offset at around -8 is probably the best balance.
Jason, it would be interesting to compare a bright scene in high bulb mode with a fixed aperture of -10 or so, against the same scene shown on a wider ranging auto-aperture in low bulb mode. I suspect you will actually get more pop in the former.
I was looking for a chart that showed how the Sony's change contrast based on aperture, and I can't find it. However I seem to remember that they are less influenced by aperture position due to their different optic assembly.