If airbus has to be faulted then this one is a definite draw back. During initial training sometime there can be follow me on controls stage, which is not possible on AB FBW because side stick movements are not duplicated and dual input is absolute no, no as it doubles or cancels the input. You can only press take over button and do the needful. There is no lag but you may forget to press so need to be ready with the button. Also the other pilot doesn't learn much as his stick remains unmoved. In airbus you perceive everything through eyes.