I have owned both a 3.5 ecoboost and 5.0 F-150s.
I put about 90k miles on a 2013 3.5 ecoboost and now have 20k on my 2018 5.0. I use/used them the same way, mostly commuting to/from work with a few long trips and occasional towing. All of the towing has been a Corvair on a U-haul trailer.
Overall my gas mileage has been about the same, maybe slightly better with the 5.0. That is likely due to the 10-speed transmission vs the 6-speed on the 3.5. The 3.5 did better when I tried hard to be easy on gas, but worse when I was having more fun with the power.
In terms of power delivery, the 3.5 had a slight flat spot right off the line or if you floored it from a steady cruise as the turbos spooled up, but I got used to it very quickly. I just learned to hit the gas a moment before I needed to get moving quickly. It was nothing like the old 80's and 90's turbos that some of us older guys are familiar with. And once past that, it would press you back into your seat until you let up on the gas. I used to say that every gear was the right gear with that truck once the boost kicked in. I was amazed at the grades I was able to climb without a downshift.
When towing, the 3.5 took a moment or two to get moving but, after that, it had no trouble at all accelerating with a car on a u-haul trailer. The 5.0 also had no issues with the trailer, though it had to rev a little higher to get the same level of acceleration. If I expected to tow more often I would probably have gone with another 3.5.
Overall, the power of the 3.5 caused me to break out in more silly grins than does the 5.0, but the sound of the 5.0 is soooo much better than the 3.5. And the power is nice and smooth, where it was a little "lumpier" in the 3.5. Having had both, I think that you would be happy with either one. They are both far more capable than you are likely to need and should last longer than you will want to keep the truck.
I had a 2.7 ecoboost as a loaner for a month while I waited for my truck to arrive, and it was also very impressive. The delay of power due to boost building up was shorter, but it was not quite as strong as the 3.5. Just driving around town it felt as strong or stronger than my 5.0 does, but it also had a slightly "lumpy" power delivery that made my happy that I bought a 5.0.
Both of my trucks (and the loaner) were/are almost identical Supercrew XLT 2wd.