I actually prefer the greyish white coloration of Cartier "white" gold. It is not as glaringly white and softer. Interestingly, in the Cartier website in French ... "White" gold is "Or Gris" - grey gold ... Even with diamonds.
I have the older transformable "or Gris" love ring pendant (c.2007) and it is distinctively greyish as it ages. My newly acquired "or Gris" love ring with three diamond are whiter. I do have a feeling that it is rhodium plated as I was trying to lightly buff off the minor scratched with my own jeweller rouge cloth it is not as easily polished as my older Cartier rings...
Note that most white gold from EU are palladium-bleached - hence the slightly higher price c.f. Rose gold or yellow gold. Palladium white gold tends to - you got it - have a greyish tint to it
It is indeed a personal preference

rhodium plated white gold are very beautiful also.
For Tiffany and most North American white gold ... Depends on the recipe - they use nickel or silver to bleach the gold to white. Costs less and much whiter, but with the potential issue with nickel allergy

Hence most of my white gold jewellery are either Cartier, Hermes etc or custom-made with "19k white gold" (18k white gold with palladium)