Ok, now this is interesting...
I was experiencing the widely reported staining, took my MacBook into the local Apple Store, the next day had a new palmrest (they said up to a week, so I was very pleased). It was the different texture I'd heard people mention, and it felt better too, and of course was nice and clean.
3 weeks later, it's staining again. This time, it's darker (less yellow) but still the same type of shade (i.e. not just dirty). I've been keeping my hands extra clean after having gotten this fixed once, and while I know my hands tend to sweat, I make sure I wipe them off regularly. Interestingly, it's far heavier on the right side, though that hand does stay there most of the time while the other one is only used for typing. My trackpad button, as before, is also discoloring, and so are some of the lower keys (the arrow keys, spacebar).
Anyone else had problems with the version 2 top case?
jW