Primary Resistance Starters: How does soft start compare to primary resistance starting?

Compared with primary resistance starters, soft starters are more flexible and reliable.
Primary resistance starters offer limited performance because:

• start torque cannot be fine-tuned to match motor and load characteristics.
• current and torque transients occur at each voltage step.
• they are large and expensive.
• liquid resistance versions require frequent maintenance.
• start performance changes as the resistance heats up. So multiple or restart situation are not well controlled. 
• unable to accommodate changing load conditions. e.g. loaded or unloaded starts.
• they cannot provide soft stop.