I've noticed that the air filters you can buy from the dealer parts counter differ from the factory OEM filters; Mazdas for example, when I last purchased an air filter for one of the 2.5 Mazda3 at the dealer, it was simply a Purolator inside a Mazda box, right down to all the markings and numbers on the filter compared to a Purolator available at my local parts store. It defintely differed from the factory OEM filter that had pink media whereas the Purolator/Mazda parts counter had white media. I wonder if Toyota does the same for their air filters? I recently replaced the air filter in my GF's IS250 with a Wix and found it to be comparable in number of pleats and material quality to the existing Denso filter.
For aftermarket air filters, I prefer Wix/Napa-Gold filters, more pleats than other brands in most cases and consistent quality and generally better pricing than the filter available at the dealer parts counter. In summary, I'd go Wix/Napa, then Purolator or Mann, then dealer-parts-counter, then STP/others then Fram, although I have seen many Fram air filters that have impressed me (can't say so much for Fram oil filters).