What were the positive and negative effects of rule by feudal lords

Positive effect:
Benefited the people at the top.
A flexible system making power and decision.
Allowed stability and security.
The lord had a unique relationship with his vassals.
Created an obligation for the powerful to help and protect the weak.

Negative effect:
90% of population were were commoners or peasants.
Serfs has no say in that time.
The kings were not in direct control of all their subjects.
Relied on gaining status through work and power.