What’s better Ford or Chevy ?

All you're going to get here is a hodgepodge of people telling you what they think is better. Many of them are traditionalists, loyal to the brand their dads and grandads indoctrinated them into believing is the best. The rest have more legitimate thoughts based on experience owning such vehicles. But all different makes of pickup truck have their highlights and shortcomings, like everything else. The only way you're going to decide which vehicle is right for you is by going out and test driving them and see which one you like the best. Seriously. Asking this type of question here is like asking monkeys when is the right time to eat bananas.

Ford PICK UP trucks are in the HOLY BIBLR. the eighth deadly sin is driving an UNHOLY, DEMONIC, SINFUL japanese prius

I hae always prefer Ford over Chitties any day.

From your question you are referring to small trucks. If that is the case then the most reliable is the Toyota Tacoma. It also has the highest resale value. None of them get good fuel mileage. 

Pretty good article that should give you what  you want to know. Comparison to Colorado, Tacoma etc.

https://cars.usnews.com/cars-trucks/ford/ranger

Fifteen years ago, I would have said Chevy/GMC all day. However, they have pretty much given up on quality control. Ford trucks aren't even close to being the best, either, but they are now way more reliable than Chevy. 

I'm not a fan of the new Rangers because the only available engine is a turbo charged 4-cylinder. Turbo charged engines tend to wear out faster than their naturally aspirated counterparts. Expecting a 4-cylinder engine to propel a 4000 pound truck, plus tow a trailer that weighs as much as 7,000 pounds will wear it out even faster. However, I guess I would choose that over the Colorado if those two were the only two options. 

I know you didn't list it as an option, but I recommend the Toyota Tacoma. They will last forever with basic maintenance, and even the [naturally aspirated] 4-cylinder engine makes enough power to get you where you need to go. If you need more power, the V-6 model is excellent. 

If you're going to buy a late model truck less than 10 years old and you want a  diesel, get  Chevy Durmax with the Allison transmission. If you're going to get a gas powered truck, buy a Ford. 

I have owned one truck of each and have had little problems with either, but I prefer Fords. I've owned five Ford cars and two Dodge cars. The Fords were much better than the Dodges.

My father was very mechanically inclined over his 85 years and owned and worked on a LOT of cars of many brands in his life time. He always said he had the least trouble with Fords.