This has not been my or my Son's experience. We have received reliable service from our 5.3's. Overall they are great engines.
There is a lot of evidence showing lots of problems as well. Not every engine is going to go bad, but a lot of them have. I have a friend who has had pistons and rings replaced because of this, in an engine with under 60,000 miles. Fortunately he had the extended warranty. Another friend of mine had a tahoe with the 5.3, same problems, that he got rid of.
One need only look at the intake valves and see how coked up they get. Plenty of pics online to show that. I have a silverado 2017 with the 5.3, I'm running the chip, and plan on using intake valve cleaner every summer. And crossing my fingers. Maybe even get the tune like mooseman said, but I'll wait until the 3 year warranty, or whatever the base warranty is, expires.
If you have one without problems, then yes they are great engines.