Brilliance
Moissanite have more sparkle because it's refractive index 2.65 – 2.69 weather Diamond have less sparkle compare to moissanite because it's refractive index is 2.42.
Hardness
Moissanite scored 9.25 on moh hardness scale and comparative Natural Diamond scored 10 on moh hardness scale
Clarity
Moissanite and Diamond is on same level on this point because both diamond have their clarity different clarity level like FL, IF, VVS1, VVS2 VS1, VS2 and so on. Moissanite's clarity level starts from VVS1 and diamond's clarity level starts for FL level.
Price
Moissanite is an affordable diamond comparatively natural diamond is expensive diamond.