I have yet to decide if I like my coir mix on other genera yet.
I've tried it on some miltoniopsis plants I have - AFTER they were not doing well - so can't tell if the coir had anything to do with their continuing to not do well or not - I've concluded for whatever reason that in general this is not a good genera for me.
I've actually tried it on a young catt seedling that was also struggling and it seemed to do well in it. Everyone in my orchid society uses medium bark with perlite and some also charcoal, so I'm a little afraid to stick my healthy catts in coir.
I have now put two paphs in coir that had absolutely ZERO roots and have re-rooted them and this has been exciting.
I've tried mixing it with bark with Cymbidiums and zygos - seems to work OK. Actually I've mixed it with fine bark with a few oncidiums too - not sure yet how well they are adapting to it - was hoping to use it to keep them a little wetter than usual and see if this would keep their pseudobulbs from shriveling.
Needless to say - I'm still in the learning stage. I may NEVER get out of the learning - testing phase?
Have you found it works well for your oncidiums?