  We show that the fundamental groups of any two closed irreducible
non-geometric graph-manifolds are quasi-isometric. This answers a question of
Kapovich and Leeb. We also classify the quasi-isometry types of fundamental
groups of graph-manifolds with boundary in terms of certain finite two-colored
graphs. A corollary is the quasi-isometry classification of Artin groups whose
presentation graphs are trees. In particular any two right-angled Artin groups
whose presentation graphs are trees of diameter at least 3 are quasi-isometric,
answering a question of Bestvina; further, this quasi-isometry class does not
include any other right-angled Artin groups.
