I found some info a few years ago on oil filters. I was doing some research for my racecar motor. It was some testing that an engineer did. Basically, the quality and ability of the off brand filters just didn't hold up. At least most of them didn't. I was surprised that Fram didn't make a good showing. Purolater didn't either. All OEM's did very well.
I run mostly all Kawi motors now. I got an off brand filter not to long ago. I was told by my dealer that it was "high" quality. I compared the 2 of them. You could tell by just looking that the Kawi filter was of much higher quality and workmanship than the other filter. Needless to say, those filters will not go on any primary motors I have.