Dallas has had the best bench in the NBA and has all season long. This isnt an opinion, it's a statistical fact. Overall, the Mavericks' bench had the best plus/minus of any in the league by a decent margin. The Mavericks have a guy coming off the bench who would start for all but three or four teams in the league and two other guys who would start for over half the league. Hell, Corey Brewer was a starter in Minnesota and is lucky if he sees the floor in Dallas.
Everyone is now acknowledging that the Mavericks have the best bench because it is undeniable, but many earlier this season refused to look at the stats. Adding Peja only furthered the Mavs advantage.