2017: love it (still have it). About 65,000 on it and it runs great. Does not feel underpowered at all. I don't tow heavy regularly and it really is a daily driver, hence the reason for the 2.7. I average about 20 mpg combined. On road trips I can get about 23-24. However, towing those numbers drop fast to around 10-12 depending on the load.

2018: the 3.5 is an awesome engine. Slightly lower overall mpg (17-18 range) towing mpg is slightly higher by 1-2 depending on load. I absolutely hate the 10 speed. It was jumpy and rough. The only way it became bearable was getting an aftermarket tune.

The 2.7 with the 6 speed is a pretty bulletproof bet. Maybe the newer 10 speeds are better, but I don't know. In the end each of the engines has the + and - . I was all set on the 5.0 going in to purchasing a truck, until I drove the ecoboost.