When it comes to trucks, the less sound the better imo so how good they sound is irrelevant to me. As far as power, it's substantially faster when merging. Me and my buddy's just went out with two 3.5 EB trucks a '15 Sierra 5.3 and a 5.0 f150. The ecoboost wins by a freight train from a roll but slightly suffered from a dig. As far as gas mileage averages they are:Did you read the articles? Each articles' real world tests conducted disagrees with your opinion.
There is not a soul on earth who would argue that the 3.5 sounds better than the 5.0. It sounds terrible. At best you'll find someone so disinterested that they won't care.
The two equivalent trucks are trapping the same speed in the 1/4. 5.0 vs 3.5 power is marginal at best. I've spent enough time in one to say I believe the the 3.5 is interesting and different, nothing more.
2016 f150 3.5EB- 21mpg city/hwy
2014 f150 3.5EB- 20mpg city/hwy
2014 f150 5.0- 19mpg city/hwy
2015 gmc sierra-18.5mpg city/hwy
(These are just the averages they all get driving to and from work so different drivers could vary I guess)
These are our own amatuer tests and we aren't paid by car&driver