He's stronger (obviously), and none of Sadow's artifacts are quite as powerful as Ragnos' Scepter, it seems. Pity that the Scepter could be destroyed by a mere lightsaber slash, though, seeing as other artifacts like the Muur Talisman and the Kressh Gauntlet couldn't, and their creators weren't really more powerful than Ragnos (well, Muur, perhaps, but they're still in the same power class).
There''s also the fact that Sadow's emergence as a spirit never quite caused the turbulence in the Force that Ragnos' did. Then again, Sadow's tomb was a more potent nexus than Ragnos'. Ragnos also literally withered Tavion after possessing her because her body couldn't withstand his corruption, whereas the likes of Eison Gynt never quite suffered such effects when Sadow possessed him.