I consider the third option worse, because it is better to choose the right map for your application than a map that is not optimal for any application.
Mercator is an angle-preserving map, so it is appropriate for navigation, but not for giving you a global view of the Earth, for which an area-preserving map is more useful.
Because I do not know the purpose of your map, I cannot judge whether Mercator is a good choice or not, but Mercator and similar navigation maps are seldom useful today, when navigation should be planned by computers, not with ruler and compass on a physical map.