A 5+ year record of satellite measurements of nitrogen dioxide columns from the Ozone Monitoring Instrument (OMI) is evaluated to establish the quality of OMI stratospheric NO2 and to test our understanding of NO2 in the stratosphere. The assimilation of OMI measurement data to retrieve stratospheric NO2 is described in detail. Over remote areas the forecast model state is generally within 0.15x10^15 molecules/cm^2 of the analysis. Dutch OMI NO2 (DOMINO) and Standard Product (SP) stratospheric NO2 columns are consistent within 0.3x10^15 molecules/cm^2 (13%) with independent, ground-based measurements, which is comparable to existing inconsistencies (15-20%) among ground-based techniques. On average, DOMINO stratospheric NO2 exceeds SP by 0.2x10^15 molecules/cm^2, but larger differences occur on the synoptic scale. Overlapping OMI orbits poleward of 30 degrees make it possible to extract information on the diurnal variation in stratospheric NO2. In the Arctic, the daytime increase of NO2 has a distinct seasonal dependence that peaks in spring and fall. Increase rates inside the denoxified Arctic polar vortex are low, whereas high rates (>0.4x10^15 molecules/cm^2/h) are found in the NOy-rich air outside the vortex. A multilinear regression to the DOMINO record shows a distinct Quasi Biennial Oscillation (QBO) in stratospheric NO2 columns over the Tropics. The QBO's amplitude is comparable to that of the annual cycle and is stronger over the Southern Hemisphere than over the Northern Hemisphere. DOMINO observations (2004-2010) over Lauder are consistent with the ground-based stratospheric NO2 measurements collected at this site, with near-identical trends for DOMINO (+0.4%/decade) and for ground-based (+0.6%/decade).