Which GPS is best for Mexico?

We rely on a small, 3 or 4 year old Garmin and found it very satisfactory. Of course, there are times when....on a road in Cape Breton an argument erupted, I wanted to follow the highway, DW wanted to turn as the GPS noted. I turned to maintain some harmony and we bounced along residential side roads until we made it - back to the highway. Another Nova Scotian faut pas was heading south from Cape Breton to the Halifax area, the wind was becoming a serious enemy, so we decided to head for the Walmart in Antigonish. Following the GPS instruction, we ended up in a residential area on a dead end street, with a circular turning circle that was not big enough. As we unhooked the towed car, a friendly chap (and aren't they all are in Nova Scotia?) trotted up with the pre-printed, detailed map on how to get from there, to Walmart! He mentioned that a lot of traffic came through there, all relying on Garmin, even semis that had trouble with the overhead wires.