Can't speak for their claim, but I can somewhat answer the rest.
I use Valvoline products currently, may not in the future.
General consensus is that their oils tend to have a weak additive package in comparison to other brands. One example is no moly in in gasoline oil formulations (it is used in their diesel formulations). In addition, their dino oils seem to shear back rather quickly. On top of that, their Synthetic Product, synpower, is a group III base oil and not a true synthetic oil like Mobil 1 etc..., although it still gets priced like one. And, on top of that, a lot of their product line can be called gimmicky, witness the huge new line of Maxlife products (the motor oil is decent) like ATF, Antifreeze, etc... Its also tough to get a striaght answer out of tech support (although who makes it easy these days?).
All that being said, the three samples I have had, one durablens sample looked great and had plenty of life left - Vis and TBN were great- currently running it out to 5,000 miles. Another had good wear numbers but was DONE - there was no more mileage to be had on that sample - it had sheared back way into 5w20 range and the TBN was 3.5. The only dino sample I did was at 3500 miles and had sheared back to nearly a 20w. TBN was good, tough to gauge wear due to a bad air filter. I'm running Durablend in it now, so we'll see how it compares...
I was desperate for MaxLife to become available here. Just after Oz release it was apparent they had down specced the oil (removed all the moly I think). They have a good diesel oil I believe, but your right they get very little traction on this site.