OEM or Aftermarket O2 Sensors?

Has anybody had experiance is using after market O2 Sensors.. I don't want to pay over the odds for an OEM part!... I have heard the After market versions don't work and are a waste of money??. Advice welcome.. 4.6Hse, 1998

hi, I have just replaced my O2 sensors with ones from Famous Four - Independent Land Rover Parts, Accessories, Sales & Servicing Specialist - Land Rover Parts, Land Rover Accessories, Land Rover Vehicle Sales, Servicing & Repair, £50 each, they are a very good price and are lucas in an intermotor box, which are a good reliable part, they are perfect, with them being lucas branded is as good as it gets as the system on my car is lucas. I would generally stay away from cheap products from china and the like.
hope this helps some.
see what theres say.