Not since carbureted engines has this been accurate. Since we now have fuel injection, shutting the engine off for a few seconds saves more fuel than a restart. There's various numbers around the web, but I believe 10 seconds of off time is worth it. Here's some sources:
https://afdc.energy.gov/files/u/publication/which_is_greener.pdf
https://slate.com/technology/2008/05/is-it-more-efficient-to-leave-your-car-idling.html
I have only driven one rental car with this feature. It was a shock at first, but after the first day I was over it. No real affect to my driving a manual transmission, but it restarted when I took my foot off the brake, so by the time I was applying the gas, I was ready to go. I haven't experienced this in an automatic truck yet.
I would think this is more dependent on one's driving situation. I only have a handful of stoplights in my town. Most places I go involve very little sitting still, so I'd leave the feature on. I could see it being very beneficial or very annoying depending on different conditions.