I fitted the blue Ritchey v-brake inserts on the XT BR-M739 brakes on my Clockwork. I also have red Ritchey canti pads on the Royal tourer (ST-X cantis) I bought from LGF.
While the pads seem perfectly decent in normal use, I have found that both bikes suffer from brake fade on long steep descents, the pads having a tendency to lose effectiveness and produce a grinding sound and feel on prolonged use.
To be fair, it is very hilly around here, conditions are not typical. Also both bikes have modernish rims with machined braking surfaces which could be contributing, but my other bikes, which are fitted with various different types of pad do not suffer from this.
I really should try some different pads on the bikes mentioned to check it’s not a coincidence...
But I thought worth sharing my experience.
FWIW I also reckon that the Ritchey pads themselves are just rebranded Fibrax pads. Packaging for mine indicated that they had come direct from Fibrax. Not necessarily a bad thing, have fitted plenty of Fibrax pads in the past without issue...