Feedforward control can significantly improve the performance of a motion system through compensation of known disturbances. Recently, new feedforward algorithms have been proposed that exploit measured data from previous tasks and a suitable feedforward parametrization to attain high performance. The aim of this paper is to analyze the accuracy of these approaches. To achieve this, related results from closed-loop identification are exploited in feedforward control. Furthermore, a new algorithm is proposed that leads to optimal accuracy. The results are confirmed in a simulation study of a motion system.