MSB Link II vs. Musical Fidelity X-DAC

i've been using the musical fidelity x-dac w/a toslink cable and have been quite happy with its performance. i've been thinking about upgrading my system on another floor of my house and have been looking at the msb link II DACs but one seller commented that they worked less well with toslink cables. any ideas why/comments?

ps - the x-dac goes into a creek 5350se w/b&w cdm1 nt speakers. the to-be-updated system goes into older b&w speakers w/a yet to be purchased amp - i'm considering another creek or a musical fidelity a300 or a3.2 integrated amp