Hi and welcome.
I'm not a mechanic mearly an enthusiastic amateur who loves a modern classic. I have a 2005 X350 and the ride is superb, I also have a Bentley Brooklands with the hydraulic suspension.
Personally I find the Jaguar a much smoother ride, it handles beautifully in the corners and smooths out those rough road services.
As a driver I would highly recommend the X350.
Good luck with your road testing and future car.