This paper presents a performance evaluation of the parallel-plane magnetic strip transmission line in the framework of the frequency-domain quasi-TEM approach considering the case of wide strips. The transmission properties of the magnetic transmission line (attenuation, phase velocity, group velocity, dispersion, and characteristic wave impedance) are evaluated and compared with those describing the dual configuration of familiar parallel-plane electric strip transmission lines. Results obtained show that, for very high frequencies, the magnetic line can perform better than the corresponding electric line. This suggests that the parallel plane magnetic strip line can be useful for microwave and terahertz applications, provided that new-generation high-permeability high-frequency magnetic materials can be produced.