The new copper/nickel brake tubing is a close second to stainless,with a few advantages--its easy to flare compared to regular steel tubing and bends easily with less chances of kinkage..
I feel its a better choice for those who aren't up to spending 200+ bucks on brake tubing when the truck might last another 5 or so years,its pretty much the same as stainless as far as lifespan..(it'll outlast the truck probably)..you can buy 25 foot rolls of it for under 40 bucks for 3/16" and 60 for 1/4",and fittings are available cheap now at Autozone,etc..
If you have ever tried to re-flare a stainless brake tubing you know how tough it is to compress and not have it split at the flare with typical double flaring tools..
Yes,you should never have to mess with stainless tube,but in the real world the fittings can strip or round off,or seize onto the tubing after enough exposure,and you may have to re-flare the line down the road if one got damaged,etc..
I realize the whole idea behind buying pre-made lines already bent like originals is to avoid ever having to replace them again,and the drudgery of cutting and flaring your own--but sometimes the way the "pre-bent" tubing is formed it is very difficult to install,even with a lift,you end up having to tweak and bend them getting them threaded in position--original brake lines were likely installed before the cab and bed were installed..
I've helped a few friends install stainless lines and it was not easy and frustrating even with a lift..a '62 Nova a friend had took us most of the day to install the tubing and new hoses,some parts had to be removed to get the lines in place ,and we still had to bend them a bit to get them in where they belonged...he does a lot of brake lines at his shop and said "I think I could have made all new lines from the roll of copper-nickel stuff faster and easier"...(and for over 100 bucks less)..
One thing I'd reccomend if anyone uses the copper-nickel stuff,leave enough "slack" so if you ever need to replace a wheel cylinder or brake hose later on,so you can cut the tube off at the fitting and re-flare & install the fitting--the tubing tends to expand into the fitting when tightened and next time you go to unscrew it,the tubing will wind up and twist off instead of the fitting spinning freely..so far that is my only dislike about the new copper nickel tubing..