The resilience against non-idealities of hot-carrier multijunction solar cells (HCMJSCs) is assessed and compared with two references, namely a multijunction solar cell (MJSC) and a hot carrier solar cell (HCSC). We investigate the impact on the efficiency of three deviations from the ideal case: nonoptimal design, internal limitations, and nonstandard operation conditions. We show that the HCMJSC maintains a high efficiency even when materials with nonoptimal bandgaps are considered, broadening the range of candidate materials for its implementation. We also show that the requirement for hot carriers’ thermalization is much less stringent than with the standard HCSC architecture, allowing to surpass the best MJSC efficiency with currently achievable thermalization coefficients. Finally, we estimate the influence of nonstandard illumination by varying the AM spectrum and estimate numerically the yearly averaged efficiency of devices installed in two different locations. Preliminary results on temperature dependence are also presented.