In general I will still say that the best RAW converter is the one you are most familiar with, also with X Trans files.
With all due respect, this is the sort of answer that I hear from those who are invested in a particular raw convertor and don't want to entertain the possibility that there might be something better. Every comparison that I have seen of Photo Ninja and ACR/LR with X-Trans files shows PN to be far superior. The same is true with other cameras and sensors. I have performed countless head-to-head comparisons of PN and ACR with files from a Sony RX1 and a Pentax K-5, and there is nothing that I can do to bring the ACR images up to the level of the PN images. It's not simply a matter of default settings. I can work for hours in ACR and not equal what I get from PN with relatively little effort. Run the comparisons, and see for yourself. Just take the time to learn how Photo Ninja's defaults and adjustment tools work.
I can understand how one might prefer LR, because of it's workflow and organization, but not because of its IQ.