The metalized paper capacitors are smaller in size than the conventional paper capacitors. However, these capacitors are appropriate for only low current applications and are now replaced by metalized film capacitors.
The mica capacitor uses mica as the dielectric medium. Mica is inert in nature and hence the physical and chemical properties do not change as it ages. It provides good temperature stability and resistance to corona discharge i.e. electrical discharges due to ionization around conductor. However, the cost is very high and due to improper sealing the capacitor is highly prone to moisture which increases the power factor.