Challenges and trade-offs in super-resolution fluorescence microscopy. Although the nominal lateral (xy) and axial (z) resolution of a microscope is the most prominent system parameter, the usefulness for broader or routine application depends on a wealth of additional criteria. This includes the ability to image time series of living samples and multidimensional imaging (3D sectioning with multiple wavelength), as well as soft criteria, such as the easy applicability and the reliability of the results. Notably, none of the currently available super-resolution technologies fulfill all criteria.