I like the e-assist a lot. I had a 2007 Avalanche and went to a 2018 silverado. The engine auto stop was a thunk at first, and was annoying, but 5000 miles now and I cannot barely feel it restart. Not sure if I'm. Just so used to it that I don't notice it, but I swear even focusing on it that it is now barely a shake.
The system makes the truck a rocket. It has so much torque when the electric motor kicks in. I can accelerate at highways speeds to pass or get up to speed easy (unlike the under powered, overweight Avalanche.
On a side note. If you have a older 5.3, reprogramming with a superchips unlocked power and best of all way more aggressive shifting.