I've been to the Dedham and Watertown MA service centers about a dozen times in the last four years. I've never had to wait more than 2 minutes on the phone or at the counter. I have had a couple emails get lost, but after a bump or two I got the answers I needed.
Appointments do book out a few weeks, but scheduling is pretty easy (especially now that it's all online). The one time something urgent came up with my car, they took me without an appointment, and even put me in a rental car since they were out of loaners.
I've never had service anywhere near that good when I had a Toyota or a Subaru.