i look for the one that has been recommended by people that have cut them open and looked at what is inside.
http://www.calsci.com/motorcycleinfo/FilterStudy.html
some quotes from above
amsoil-a flawed superior filter
Fram-cardboard
K&N-average filter with a 6$ nut on the end
mobil m108-nice filter media but not much of it, smaller unit (so it goes well behind headers)
Pure One PL14610- an example of fiters should be made
http://www.tobycreek.org/oil_filters/
quotes from this one
If anything, the Fram will show you how NOT to build a high performance oil filter
The Amsoil filter internally looks very similar to the Wix filter, but they are not the same. Semi-O ring gasket, well cut threads with no apparent burrs.
honda oem
This is how a high-performance oil filter should be built.
K&N
This could be my new favorite filter
mobil 1
This is a well-constructed filter, which Mobil 1 touts as having 98% single-pass particle filtration at 10 to 20 microns, and multiple-pass efficiency of 95% (vs. 80% for the average filter).