In this paper, the performance of cochannel full-duplex multiple-input multiple-output (MIMO) nodes is considered in the context of models for realistic hardware characteristics. Here, cochannel full-duplex relay indicates a node that transmits and receives simultaneously in the same frequency band. It is assumed that transmit and receive phase centers are physically distinct, enabling adaptive spatial transmit and receive processing to mitigate self-interference. The use of MIMO indicates a self-interference channel with spatially diverse inputs and outputs, although multiple modes are not employed in this paper. Rather, we focus on rank-1 transmit covariance matrices. In practice, the limiting issue for cochannel full-duplex nodes is the ability to mitigate self-interference. While theoretically a system with infinite dynamic range and exact channel estimation can mitigate the self-interference perfectly, in practice, transmitter and receiver dynamic range, nonlinearities, and noise, as well as channel dynamics, limit the practical performance. In this paper, we investigate self-interference mitigation limitations in the context of eigenvalue spread of spatial transmit and receive covariance matrices caused by realistic hardware models.