If the chemicals are the same, I don't give a rat's #$@ about the label on the container. Kind of like a pair of jeans at Costco versus a pair of Guess jeans at some designer store. They're both jeans, and they both work. One just has the perception of higher quality due to the higher cost and name recognition. For Pennzoil to claim that the fluid is compatible means they must have obtained a sample of the Shell and Esso fluid and determined it's composition. Otherwise, Pennzoil stands to lose a lot of money through potential lawsuits stemming from tranny failures. Anyways, after 5,000 miles on an alternate fluid, I've got no problems.

Similarly, I just installed a pair of DEPO headlights on my car and they look and work great. They're not manufactured by "Hella" but at one-third the price, who cares?