Comparing the Orion and Upper-Sco complexes at the same physical scale reveals striking differences in the amount and distribution of dense gas. The greyscale represents the Planck column density map (Meisner & Finkbeiner 2014), and red marks regions with dense gas (A_K > 0.8 mag) likely to collapse into new stars. While the gas mass in Orion is about twice that of Upper-Sco, Orion contains ten times more dense gas. Critically, dense gas in Orion is concentrated in two main filamentary clouds, whereas Upper-Sco’s dense gas is more scattered across the region.