I believe Wix makes most of the filters for NAPA and both are quite good filters. Many aftermarket filter brands, in order to be inexpensive (their major attraction to purchasers) use standardized internal elements which can fit inside various sized “cans” which outwardly appear to be similar to OEM filters. In other words, to keep costs down, a smaller paper-element is mfr’d to be used in various-sized cans. This means that aftermarket filters with large cans but small elements can resemble OEM filters with large amounts of media.... but sell for less.
The same is true of other internal components such as springs, anti-back-flow valves, seals, gaskets, and even the cans themselves may be cheaply crimped or thinly stamped and unable to withstand higher pressures or impacts.
Wix/NAPA are better than the cheaper brands, and there are some good Puro/Purolator filters (who, by the way, make WalMart’s “SuperTech” filters.).
While I would not pay for the inordinately-priced Mobil 1, Bosch, etc., .... I also do not fall for the high-priced/low-filtration (in order to claim better machine-performance or to allow “re-useability”) of the K & N models.
Unless you’re willing to accept the risks of lower quality along with the lower prices.... or unless you’re the believer of hyper-advertising for “designer” products.... the solid solution for owners who want to take care of their equipment without worry is to buy the OEM filters and fluids.
I admit however, on less valuable or less important equipment I frequently use aftermarket filters,... and example is my 1986 Ferguson compactor-Roller for which “Ferguson” does not make OEM filters. They re-sell other mfr’s filters painted with the Ferguson PN on them. I use the NAPA or LuberFiner equivalent and have had good results. My Sears lawn-tractor uses SuperTech rather than the “official” Craftsman-brand (which I darn well know Sears does not actually have produced by any high-quality filter mfr’r.... as I’ve cut them open and found cheap, stamped, flat-sheet-metal springs and undersized elements.)
If you’re not as ADHD as me.... then your best solution is OEM filters, and at least the Kubota filters are not overpriced.