Notes: This is not a review. I create this post for recording colour test on different base or surface
Agrax Earthshade is the new shade to replace the famous old washes, Devlan Mud. I've no experience with Devlan Mud so I couldn't compare this two. However, Agrax Earthshade is good for making some slurry effects on the model, and combine with some metallic base, it can make good rusty looks.
How it washes on Sycorax Bronze coated surface (right):
How it washes on Mr. Hobby Color H8 Silver base coated > Tin Bitz layered surface (right):
How it lightly applies on Imperial Primer primed, Leadbelcher base coated surface: