I observed that too, Mojo. This summer, when cash was a pinch, I purchased the PowerPix batts and noticed that they were either the same as E. Lithiums or better. (Visually and sound-wise) But PowerPix are alot less expensive. And for my buddies and I, who went through batts this summer, it was a welcome change of pace.
One thing with the Lithiums, they lasted a little longer than the PowerPix.