The Amsoil EaOil filters are 98.7% efficiency rated @ 15 microns. They use 100% synthetic media in construction. Compare this to cellulose media filters which can range anywhere from 40%-80% efficiency even at larger particle sizes. Amsoil rates them for 25,000 miles or 1 year.

I'm not familiar with the construction of Mobil 1 filters, but I'm sure they're better then most of the crap out there (fram, penzoil, motorcraft, etc.)

http://www.amsoil.com/StoreFront/eao.aspx

An interesting study, although it is a little old and so does not include some current filters out there (including the EaO's)
http://minimopar.knizefamily.net/oilfilterstudy.html

 

good stuff man def