Left panel: relative S/N of an atmospheric signal for all exoplanets with R_p < 3 R_⊕ as a function of planetary equilibrium temperature. The symbol size is inversely proportional to the planetary radius, emphasizing those closest to an Earth radius. The π Men c planet is used as the atmospheric signal reference and it is indicated by the filled circle. It is among the top ten most favorable planets for atmospheric characterization. Right panel: as in the left panel, simply limited to solar type host stars (i.e., G-type stars; 5280 < T_eff < 6040 K). The π Men c planet is by far the most favorable planet around such a star for atmospheric characterization. The other optimal atmospheric targets all transit K and M stars. For this reason, the coronal and stellar wind properties that interact with the π Men c atmosphere may be distinctly different to those experienced by the rest of the sample.