Yep. Two versus one really but...
On one hand you have very detailed advertising outlining elaborate testing and points of failure, by two respected companies. Way beyond the level that motor oil is generally marketed to the average consumer, but hey when you catch your rival with their pants down that badly how can you not take advantage of it?
On the other hand, you have one respected company that says "no, and these other guys say so". Oh look, is that a bunny?
Actions speak louder than words, which is the clincher here.
I am however keenly aware none of these outfits walk on water and I don't have any real preference, I have used and will continue to use products from all of them. However, the recent Rotella thread has got me thinking about HPL or Amsoil.