Each kit has a definite general dynamic feel:
Mantic - fast and reaching
Studio Miniatures - passive and lurching
Wargames Factory - awkward and lumbering
GW - vacant and static
These combine to a set of marvelously rich zombie archetypes that can (in my fevered brain) be loosely condensed into the taxonomic ranks of 'Walkers', 'Grabbers' and 'Shamblers'.
WALKERS... (click on images for larger versions + parts breakdown).
Lots more pictures, and no doubt taxonomies, to come!!