Best bet is to try to see them all side by side with your own eyes. Best Buy is the best bet for that and most stores will let you play the settings. Then you can see not only how the panels handle dark scenes, but also bright scenes and everything in between. Then you'll see if you can detect the impact of ABL in each panel.
It's also a great opportunity to see if you can detect differences in sharpness. After all, it's you that will be watching the display, not us.
One plus for the 8500 not often discussed, is the Evolution module that allows upgrades, that could include enhancements to the picture. It's not enough of a reason to buy the panel IMO, but it can be one factor in the decision making process.