This paper aims at presenting a comprehensive analysis of time-reversal (TR) as a precoding scheme for wireless communications. As exposed in the paper, TR can be viewed as a particular spatial filtering scheme with some strong commonalities with more conventional beamforming strategies used in large-scale antenna systems (LSAS). Our goal is to compare the behavior and the performance of the TR-based beamforming with that of the well-known Maximum Ratio Transmission (MRT). Therefore, we develop a generic system model for TR-based beamforming systems. Then we lead a theoretical performance analysis relying on ergodic capacity computations and based on statistical models of the equivalent channels obtained with both RT and MRT precoding schemes.