The Churchill is distinctive and positioned arguably more as a Grand Hyatt. Is it the best Hyatt Regency? I guess it depends what you compare it to. Outside of the US, you have the likes of HR Bangkok, Samui or Zurich to name just a few which are all newer and each have some form of distinctive feature.
Personally, I’d be more likely to say that the Churchill is more of an odd fit than the clear vest of the pack (with highest room rates, even with the UK having torpedoed their currency).