The only difference with a manual slider is that you must get out of the truck, release the slide, pull forward till it lock in the extended position, then back up.
If you ever forget, you will take out your back window and damage the nose of the 5er.
Certainly less expensive
I don't have to worry about it, as with my slide, I can get a full 90 degrees and never have to think about it.
Jim & Kim from Colorado
2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
Click on my profile for Mods and notes