They have a point about the bypass valve being mated to the oil pressure. I would be interested in seeing what the actual difference would be. It would be hard to test without equipment, however, to measure the parts per million before and after filtration (it would mostly be subjective without the equipment to properly test).

I personally think that if you change the oil frequently enough (like every 3k miles, or even less) along with the filter, the point would probably be moot. The actual break down of viscocity and distribution of crap in the oil would be minimal, unless you were driving in really extreme conditions or the engine was already degraded. I think it's more important to make oil changes more frequently, than to worry about which filter performs better. Just my two cents, though.

-- John