With the new design of the front cap, they claim you don't need a slider.
With that being said, I have one. I guess I'm from the old school. I would find it hard to "not" have a slider. I just like the peace of mind it gives me when we get in a tight situation. I also have the 6.5 box. A lot will depend on what type of situations you think you will be backing into---you will get closer to your back window backing up then you will going forward.
So I think it will all depend on what you are comfortable with.
By the way, welcome to the forum.
Edited by: Old Farmer
2008 Cruiser CF26RK
2013 Ford Eco-Boost
Heavy duty payload - Max tow