Which one over rides the other, Excellent Customer Service VS Good Quality?

Good products keep costumers interested, but sales and after-sales services keeps them loyal

Both are Essential and connected to the other

Good quality is one of the elements of Excellent customer service. I d say Excellent Customer Service. 

Good quality needs no explanation and serves excellent support in sales.

Good quality comes along with the relationship which has already built during the customer service stage. So, excellent customer service overrides a good quality.

a great service would surely prove a great quality which leads to a great experience 

Excellent Customer Service

Excellent Customer Service

Excellent Customer Service overrides a good quality, mainly customer service builds a relationship with a customer , good quality comes along with that relationship we build. 

I would say both are very important but good quality comes with Excellent Customer service because excellent customer service means you are working very hard to get it done at a high degree meaning you get Good quality as well.

I believe that good customer service is what brings the customer