What are the advantages and disadvantages of transistor shunt regulator?

Advantages:

• The transistor shunt regulator has a good efficiency for small load currents.
• It has eased to reject short circuit.
• The voltage regulation is good.
• It has constant DC output voltage.

Disadvantages:

• It has poor efficiency for large load currents.
• It has high output impedance.
• The output DC voltage is not absolutely constant because both V_BB and V_Z voltages decrease with increase in room temperature.
• The DC output voltage cannot be changed easily as no such means is provided.
• It can be used for large currents loads.