I have been running one for 18 months now. Two used oil analyses showed low silicates so it is filtering just fine. It's half the price of some of the competitors. Just cleaned, oiled it, and threw it back in. Good as new.
edit: 18 months = 18K miles for me
2008 IB E92 M3| BBS | KW | Arkym | Platte Forme A.G. | Active Autowerke | K&N | Fabspeed | Dinan | Evolve-R