I voted for other, because it depends...
Truly for me, I never use a grid on my own maps when I play D&D, approximations spoken in game works well enough for my group.
We used and sometimes still play Battletech - and that of course requires hex grid maps.
However, nowadays I am making maps for others and have to meet their expectations. Squares are fairly consistent for the printed battlemap market, and its what's expected. Plus D&D movement rules is usually square not hex. And if I'm creating a VTT map, then I use an implied square grid to get scale correct across the map, but then I don't include the grid with the final, as grids are inserted and scaled at the user's whim.
I use square, hex and no grid - it depends on who the map is for. :P