From what I know and what I have heard/been told;
1) it's not a case of if the original type of compensator fails it's close to a certainty and may involve a flat bed to get home. The later ones with the grease nipple are better but still not great unless they are frequently greased and the revs are kept up to avoid over-running the ramps and lots of care is taken to drive smoothly.
2) the Centa unit appears to just work (so far anyway) though it does rattle a bit if you do load the engine at the kind of low revs that S&S say you mustn't use because it will damage the engine and they're not really interested in the transmission.
3) the rubber barrels in the Centa, in common with all mechanical components, must wear out eventually. Centa have a very good reputation for the longevity of this type of system and my suspicion is that failure is more likely to be down to gradual wear on the rubbers till it reaches a point where increasing noise and play in the drivetrain will make itself felt at which point it would be an engine out job to fit new ones. I doubt if a sudden total failure is at all reasonably likely to leave you needing the flat bed.
I've had all three variants and am quite happy with the Centa - again, so far!
