What is the difference between a soft sleeper and a hard sleeper?

What is the difference between a soft sleeper and a hard sleeper?

There are 2 upper berths and 2 lower berths in a soft sleeper compartment for 4 passengers. A hard sleeper compartment is of 2 upper berths, 2 middle berths and 2 lower berths for 6 passengers. The soft sleeper compartment is of more space than the hard sleeper apartment.
The soft sleeper compartment has a door that can be closed, while there is no door in the hard sleeper.
The bed in the soft sleeper is more comfortable and wider than the bed of the hard sleeper compartment.
The soft sleeper compartment is equipped with better lights, slippers, hangers, etc., which are nor provided in the hard sleeper compartment