Which system is better from the system and a customer perspective?

1. three customer service representatives with one single server, single queue for all customers. they all line up in one line and whichever counter opens they go to (first come first serve)
2. or having poisson process and service time is exponentially distributed. I am thinking of having a dedicated queu for a dedicated server like gold members go one line while silver members go into another line, and other members go into the third line

• this questions wants to focus about the differing queues and how poisson process can be helpful. Customers can not switch lines or servers.