The green stuff was still in the bearing and in pretty good shape at 112,000 miles on my W210, and cleaning everything showed them to be in fine condition. So I repacked with the green stuff, fit new seals and 17K later it's still fine.

I had some other synthetic wheel bearing grease (mobil1 from a different car), but the real reason I used the green stuff was that if it was good for 112K, I figured I wouldn't have to worry about it for a long time. I also grew up with the old cars and the brown grease that you had to repack every year, but then we were also changing plugs, points and condensers that often, too.

I very rarely hear about the early bearing failures, too, but I have to think that if it were really the fault of the grease, such things would be lots more common.

As I typically say, though, the great thing about owning a car is that you get to decide how best to maintain it, so whatever gives you comfort, go with it.