Originally Posted by TheOtherDave™

Wix <-- I've been using them exclusively before I even bought my DC4.
Purolator
Mobil 1

Fram uses cardboard end caps, piss-poor filtration media and plastic bypass valves. All the brands I've listed use steel caps, more filtration media of better quality and steel bypass valves.

Check the FAQ... a good ways down, there's a link to a filter discussion / test on NTPOG. It's on the old link page way down near the bottom of the thread.