Agreed, I've been away from it since 2017, but we sold a pile of 3.5 EcoBoost F150's, customers loved them, they got good mileage, and we had zero problems. Our sales manager was the dealer's son and he always had an Ecoboost F150 demo if we had one in stock. He towed his 2 snowmobile trailer to Pittsburg, NH, in cold winter weather(obviously) and got mid 20's for gas mileage. We had a customer who towed a trailer all over selling welding supplies with his EcoBoost F150. We loaned him a 5.0 truck when his was in for a turbo at 150,000 miles. He thanked me for the loan, said the 5.0 was a lot harder on gas and didn't tow as well. We never had to take a 3.5 apart for anything, a couple high mile turbos was the worst we had. We sold few 2.7 trucks at the time but also had zero problems with them.
My 2016 2.0 EcoBoost AWD averaged 27.3 mpg round trip to my daughter's house near Washington, DC- going 75-80 on the highway and then in the worst city driving I've ever seen.