I know of one member who had a transmission failure in Europe. It is possibly to do with heat, the European RX has a better transmission cooler which may explain things.
All of the RXs I have seen (series I) have had poor fluid quality, not a nice bright red colour but a deep red/brown colour. I would recommend a drain/refill (not a full flush) every 20k miles. I've also installed a filter on mine.