Out of the Halo 3 figures available now i personally think the grunt is one of the best for mobility. Every joint moves perfectly!
I liked the fact the back armour comes off along with the face mask. it was the first time i actually saw what a grunt looks like behind the mask.
However, the only negative thing i have to say about this figure is that you have to be a lot gentler then you would with the spartans. as the plastic arms and legs are thinner. i have already broken mine on the left leg. but simple to glue back together! just avoid gluing the joint!
over all, 3/5