They're different artifacts.
MadVR's "ringing" artifacts come from scaling the image up or sharpening it, and usually manifest as a thin halo around sharp edges: http://photographystepbystep.com/wp-con … g-halo.jpg
The debanding just adds a bit of noise around subtle color transitions to mask the "banding" effect: https://upload.wikimedia.org/wikipedia/ … mple01.png
SVPs artifacts vary more and are quite different: http://www.svp-team.com/forum/misc.php? … download=0
In a nutshell, you should tune all of them to taste, depending on your current settings. MadVR's default debanding is usually fine unless you have some really weird animation, but the defining and svp artifacts should be tuned based on how much you notice them. There's no "best" setting for those.
However, I will say the ringing introduced in MadVR's better scalers is very subtle. I usually leave it off unless the source material already has ringing.