Energy-maximising control of wave energy converters can be separated into two different classes: optimisation and non-optimisation based strategies. While optimisationbased controllers can outperform non-optimisation based strategies, the computational requirements associated with numerical optimisation routines, and the high control forces required under optimal conditions, can render these energymaximising control laws unsuitable for realistic scenarios. Nonoptimisation-based controllers present an alternative solution, where linear time-invariant systems are used to approximate the so-called impedance-matching condition. These strategies are often simple to implement but suffer from performance degradation when motion constraints are considered. This paper aims to present a critical comparison between both families of controllers, highlighting the strengths and weaknesses of each approach. We present simulation results for a state-of-theart CorPower-like device under polychromatic (irregular) wave excitation, for both (motion) unconstrained and constrained scenarios.