What are the pros and cons of ion thrusters?

Could you elaborate on the benefits and drawbacks of utilizing ion thrusters in space travel? Are they significantly more efficient than conventional rocket engines, and how do they compare in terms of thrust and speed? Additionally, what are the potential challenges associated with their operation and maintenance, such as their reliance on electricity and the risk of damage from cosmic radiation? Furthermore, how do ion thrusters compare to other advanced propulsion systems being developed for deep space exploration?