I've used Avid revolutions since they came out and not had a single clutch bearing failure in that time......
I pull the yellow seal off and blow the grease out with either an air compressor or motor spray (I've ran them dry for years-no lube).... re-install seal and run them for about a gallon and throw them away. It doesnt matter which way you run the seal, I've ran them both and there's no difference in life.
The key to clutch bearing life if chassis flex and having enough fore and aft play. I run alot of play, 2-3mm and my car's chassis doesnt allow the clutch bell to hit the chassis. Not monitoring these 2 things will cost you a grundle in bearings....
Avid revolutions - dead reliable and cheap $1/ea
Ceramics for me have been nothing but problems