I really like our slider because it doesn't take up any room when it opens and it is very difficult to push/pull open if an animal gets into the run.
It is an "up and down" slider rather than side to side. No bedding gets caught, other than at the bottom a bit and that doesn't keep it from closing securely. It is about 6" above the coop floor. Door is wooden 1/2" thick cabinet quality ply-board, we used 1x2s for the inside track on both sides of the pop-hole so door slides up and down easily, spaced with 3/4" wooden strips. Top center of door we screwed an eye bolt, then another on a board above the door that is even with first eye and level with a small hole/opening leading outside the coop. We finished that hole with a brass grommet. A string of synthetic clothesline is tied to the door's eye bolt, laced through the eye above that and then outside through the grommet. We can open and close from outside the coop by pulling the string and tying off on a small cleat mounted to the wall. It works beautifully, is very secure, and no going inside to work it, plus it takes up no space as it slides up the wall.
Just remember that your slider track needs to be about 2x as high as your door so that when it is fully open, it is still inside the track. Also, don't make the track too much deeper than the depth of your door. Too much room and it can get wiggly, too tight and it may stick when it gets hot/cold/wet/dry.