Hi sobrino,
A forum search on Christeli Lux Estate and on Palais Grand Royale (you can just click these) will bring up more information and feedback about both of them.
The main advantages of a latex base layer would be it’s resilience, it’s point elasticity (ability to adapt and contour to a body shape), greater compression modulus (how quickly a material becomes firmer with greater compression), it’s ventilation/airflow, and its durability compared to polyfoam. It has a different “feel” that many people prefer. Of course it’s also a more costly material than polyfoam.
The main advantage of the Palais Grand Royale vs the Lux Estate is that the Palais has the extra 3" memory foam component which allows for different configurations to change the feel and performance of the mattress after a purchase (see post #6 here).
Phoenix