MWC 349 and Eta Carinae are two of the brightest radio stars in the northern and southern skies, respectively. They share another property: they are the sources with the strongest known recombination-line masers. At millimeter wavelengths, this makes them suitable targets for super-resolution techniques that allow us to probe sub-milliarcsecond scales not accessible by other means. The two sources have very different behavior at these scales. This talk will discuss the properties of these two sources and what the recombination-line masers reveal about them.