I used Ben last year for my 90K service. I was pleased and would recommend Ben to anyone. Coincidentily, I took my 500E to the dealer for my timing chain replacement, throttle body actuator, and wiring harness replacement ($$$ - wife does not know the amount yet !!) . Although I am confident that the technician will do an excellent job, I'd rate the customer service POOR...
Ben's has excellent customer service and a great group of technicians that have been together for years.