I have to admit - it was not easy getting used to letting the car slow down for me as I approached other cars on the LA freeways. I think the mistake I made in the beginning was keeping the "relative distance" setting quite low (ranges from 1-10, 1 being closest). However, the more I used the feature, the more I became a fan. I think the tipping point for me was the stop and go traffic during rush hour where the Tesla TACC can slow you all the way to zero and then pick up and eventually get back up to 75 mph without real interaction from the driver.
There is a caveat of course that the car may not slow in time. A "collision" warning sounds, giving you time to hit the break and help the car slow even quicker--but truth be told, it took a lot of tries to get to the point of bravery to test this out.
But all of that effort paid off tremendously as I took my 2nd road trip (this time to HPA Tech Retreat in Palm Spring, CA). I was able to be on conference calls the entire trip (in the HOV lane) without focusing very much on the slowing and speeding up of traffic in the various highway choke points, allowing the car to do the work for me and focusing on keeping in the lane (or changing lanes when appropriate), but also having the confidence that the car would keep an appropriate distance from the cars in front. I found that using a setting between 3 and 5 on the relative distance (based on time to the car in front of you, so more distance at higher speeds) worked the best for me. I found that at higher settings, too many cars in traffic would try to "squeeze" into the open space, creating a traffic risk of its own, and that lower than 3 made for too many exciting decelerations when traffic suddenly came to a grinding halt.
By the way, the new Tesla Supercharger in Cabezon, CA, was great. Next to an outlet mall and a McDonalds and of course with 10 charging bays. Very conveniently located right off the exit on the 10 East Bound before the LA Metro Highway area.