I didn't have one for my ps3 slim like just stood it against the wall and on my "man station shelf" below my TV haha.
I wouldn't of thought it would be a problem with the PS4. They have made a little plastic piece to stabalise the console if you stand it vertical.
Weather or not it increases the stability that much I don't know, also the price for me is a bit of a joke £16 quid for a bit of plastic.
I wouldn't recommend standing it up a lot of peoples PS3 Blu Ray laser stopped working because of it
I stood my fat PS3 on its side since release, (it still works), my slim on its side since I bought it 2+ years ago. (Still works fine).
Case proven sideways made no difference to people blu ray ware & tear.
Expect the PS4 to be just the same, otherwise they would not advertise it in that manner if it was harming the system.