With a bigger drum you can fit in larger items such as duvets, or do a big load at once.
With an anti crease spin the machine gently rotates to shake out creases.
A two way tumbler spins in two directions. This is good for efficient drying and for untangling the load.
The machine will analyse how much heat is needed in order to dry each specific load, therefore increasing efficiency and saving energy.
Gas dryers are more economical in the long run. They are a good option if you have a gas connection in your laundry room.