Are there any differences in graphics drivers from the "X-Swat" vs. "xorg-edgers" PPAs?
If the version numbers for graphics driver packages are the same, there is no difference between the X-Swat (X-Updates) PPA and the xorg-edgers PPA (because they come from the same source)
But, note that the X-Swat PPA contains only graphics driver packages, while the xorg-edgers PPA also contains many other "bleeding-edge" graphics/system packages which may be unstable; if you choose the xorg-edgers PPA, regular updates will install these other packages too.
So, if you want to update only your graphics drivers, the X-Swat (X-Updates) PPA is recommended.