Every place I have worked in my 10+ year design career (10+ places, including freelance the past 3 yrs), every designer has used a mac. That may not always be the case, but adopting the tools of the trade that are in majority use certainly won't hurt you.
Every place I have worked in my 10+ year design career (10+ places, including freelance the past 3 yrs), every designer has used a mac. That may not always be the case, but adopting the tools of the trade that are in majority use certainly won't hurt you.