What are the similarities and differences between gravitational and electric fields?

Both gravitational and electric field obey inverse square laws (e.g. F(grav)=GMm/r^2 and F(electric)=kq1q2/r^2 where GMm and kq1q2 are constants). They both act between two bodies without any means of contact. However gravitational force acts on mass while the electric force acts on charge. Gravitational force are only attractive while electric field can be attractive/repulsive. Electric field is much stronger than gravitational field.