Generally, ‘地道’ and ‘道地’ both mean 'authentic, genuine'.
However, just like you said, different Chinese people have used different. In mainland China, people usually say '地道' while Cantonese speakers and people living in Taiwan are used to '道地'.
Actually, '道地' was used in mainland in the past as well, so it won't surprise
me if you see this word in books or hear it on street in certain context, but '地道' sounds more natural in daily speaking.