Mercedes S Class
In terms of ride quality and quietness I would get the Chevy Cruise.
The maybach is the the most comfortable car it has reclining seats in the back along with a mini fridge and t.v. but it is priced around $400,000.
The 2009 models with the smoothest ride that cost under $40,000 are the Buick Lucerne CXS and Lexus ES 350. Both of these cars have comfortable driver's seats. You may be able to find a car with more comfortable seats, but these two models are the only new cars with a fantastic ride for under $40,000.
Of the 3 in the categories you chose the lincoln will be the most comfortable.
Bently
That is subjective. What is comfortable to you or me may not be comfortable to others. In most case the more expensive the vehicle the more comfortable the seats.
2010 M6
Longer tire life, reducing wear on suspension components, more comfortable ride.
A more solid feel, more comfortable ride, more stable, likely safer in a collision.
i believe the most comfortable car seats in the world are the seats from the Volvo S80 from '99 to '07.the new generation lost something.
Mercedes s class
Brett's tank seats.