  Rydberg electromagnetically induced transparency (EIT) enables realization of
atom-based SI-traceable microwave (MW) sensing, imaging and communication
devices by exploiting the strong microwave electric dipole coupling of highly
excited Rydberg states. Essential to the development of robust devices is a
careful characterization of sensor performance and systematic uncertainties. In
this work we present a comparison of microwave-induced EIT splitting in a
cesium atomic vapor for four possible Rydberg couplings $65S_{1/2}\rightarrow
65P_{1/2}$, $66S_{1/2}\rightarrow 66P_{3/2}$, $79D_{5/2}\rightarrow 81P_{3/2}$
and $62D_{5/2}\rightarrow 60F_{7/2}$ at microwave transition frequencies around
13 GHz. Our work highlights the impact of multi-photon couplings to neighboring
Rydberg states in breaking both the symmetry and linearity of the observed
splitting, with excellent agreement between experimental observations and a
theoretical model accounting for multi-photon couplings. We identify an optimal
angular state choice for robust microwave measurements, as well as
demonstrating a new regime in which microwave polarization can be measured.
