This is an age-old question and you will get many answers, all valid for that person and his or her truck and trailer combination. I have an antique trailer with a very square front and I use my slider every time I pull into a campground. Watching the corners is one less thing to worry about. Given the difference in cost between a slider and a nonslider, you could pay more than that for one mistake that crushes the corner of the truck and takes out the rear window. Good luck and welcome to the forum. Lots of good people here!
Bob