A lot depends on your "non-towing" use. If your daily commute and around town driving is typically only a few miles/minutes, it probably wouldn't be enough to warm a diesel up to proper operating temps. That could cause you some maintenance issues and (potentially) shorten the engine life. If, on the other hand, your daily commute is 20-30 minutes or more, a diesel might be a good choice for you. Also keep in mind that diesels are rarely available in a 150/1500 series truck. You generally have to move up to a 250/2500 series, which also beefs up the frame, tranny, suspension, etc. That may be why you didn't feel the trailer when you towed with your buddy's diesel P.U. If you never plan on "upgrading" to a 5th wheel or a trailer over, say, 8000 lbs., a heavy duty truck is overkill.
I have an F-150 Ecoboost, and I love it. If the legendary "turbo whine" exists, I don't even hear it. (And my hearing is pretty darn good.) The torque and compression are excellent, and the acceleration is flat out amazing! It pulls my Eagle with ease - both up & down hills. Though I've not yet pulled it through the mountains, a buddy's BIL reports passing diesels right & left while towing his through mountains. One thing, though, don't expect the 22/23 mpg Ford advertises. That's a 2x4/Standard Cab without the towing package. 4x4, Crew/Super Crew Cab, and Max Tow Package will add considerable weight to the truck. I get about 17.5 hwy./12.5 city/14-16 combined. Towing my Eagle drops it down to 7.5 - 8.5, but it's 30 feet long and weighs in at around 8K.
If it were me, I'd stick with the F-150 gasser. But that's JMHO . . . FWIW!