Pressure Assisted

Uses water pressure from your water line to build air pressure inside a sealed tank that forces the water through the bowl for better cleaning.

Pros: More effective. Less likely to cause clogs in plumbing.

Cons: The loudest type of toilet, which can be a drawback in small homes and if installed adjacent to a bedroom. Requires 25 pounds per square inch of water pressure to function, which you can test with a $10 gauge. More expensive than other types of toilets.

Gravity

This toilet uses gravity as water that is stored in a tank above your toilet bowl falls through the bowl when the lever is pressed.

Pros: Relatively quiet, wide variety of models, inexpensive.

Cons: Not as effective as pressure assisted toilets.

Vacuum

Uses a vacuum chamber inside the tank to pull air out from the bowl allowing it to backfill with water.

Pros: This toilet is quiet and efficient.

Cons: Not as effective as pressure assisted toilets. More expensive than most toilets.

Dual Flush

A new method of reducing water usage.  Choose between two flush modes: a low water usage mode for liquid waste and a more water mode for removing solid waste.

Pros: Less water usage.

Cons: More complicated and expensive