They perform different functions.
Cam-guard is to prevent corrosion of the cam during periods of in-activity.
Avblend is to reduce surface roughness, which reduces wear and improves ring-wall sealing.
From the Avebend ligature:
"AVBLEND uses your aircraft's engine oil as a carrying agent to reach metal working surfaces inside your engine. When your engine reaches operating temperature, AVBLEND soaks into the metal surfaces. Once AVBLEND has penetrated the internal components of an engine, the parts are continuously lubricated and cleaned. Continuous use of AVBLEND helps reduce future harmful carbon deposit buildup.
If you were to look at the metal in your engine through a microscope, you would see that the surface is far from smooth. You would see peaks and valleys, blunt and sharp edges. Your aircraft engine's oil moves over the surface doing its best to provide lubrication. However, the oil molecules are too large to provide penetration in the small grooves and protect the entire surface of your engine. AVBLEND's depth-soaking molecules are small enough to fill in these tiny nooks and crannies and penetrate deep into the metal, thus providing better lubrication with moving pieces. Plus, AVBLEND cleans the surface from harmful deposits."
I think the consensus is that aircraft engine tolerances are not tight enough for this technology to have any appreciable improvement in life or performance.