I have had USAA as my car insurance company for over 40 years.
I had sold my car before going on active duty with the U.S. Air Force where I was sent to Mather AFB to attend the USAF Institute of Air Navigation. While there I purchased another car and, on the advice of some fellow classmates and friends, I purchased insurance for the car through USAA. I have been very happy with their low rates and excellent service.
One of the side benefits of insuring with USAA is that their reputation for low rates and excellent service is such that any time I am contacted by agents from other companies all I have to do is say that I am currently insured with USAA and they immediately abandon their sales pitch knowing that they can't compete with the price and service I am currently receiving. I don't have to turn these other sales people down as they instantly give up on their own.