What kind of cheap sliding discs do they have @ Walmart?
I have furniture gliders (which are like Valslides) and the original Gliding discs (Mindy Mylrea's, which are the same as Cathe's, I think).
I use them both.
I find the Gliding discs do better with circular movements (sweeping movements) and moving laterally. Makes sense because of their shape. (But tend to clack together when doing forward/back lunges, which annoys me.)
The furniture movers do better with linear movements (front and back only). Because they are narrow/rectangular, I find they are a little jerky if I try to go to the side or make a arc motion.
I think they are equally comfortable
and uncomfortable to use, though my foot does tend to slide off of/require readjusting on the Valslides more often than the discs.
BUT...by no means have I done thorough scientific research on this, LOL. These are just some quirks I've noticed (could be my carpet!)
I'd probably suggest trying the cheap ones out...