What are the differences and similarities between charge and mass?

Similarities:

a) Charge and Mass are scalar quantities.

b) The Electrostatic Force associated with Charges follows an inverse square law, while the Gravitational Force associated with masses also follows inverse square law.

Differences:

a) Unit of charge is coulombs (C), unit of mass is Kilogram (kg)

b) The force associated with charges is electrostatic force, the force associated with masses is gravitational force.

c) The law governing charges is Coulomb's law while the law governing masses is Newton's law of gravitation.
(the difference here is in the name of the persons who postulated their laws)  

Definitely the indoraptor