Lots of people use hexes. It clears up some problems (diagonal movement for example, the "half" the battlefield with shield, etc). I have both a grid and hex battlemaps. I tend to use the grid for D&D mainly because the rules "assume" a grid and because my interior maps tend to come out wonky on them.
I use the hex map for Battletech and Mechwarrior RPG. Again, because the rules tend to "assume" a hex map and it just makes it easier.
I don't think you'll run into too many problems using a hex map for D&D. Use whatever floats your boat.
IceBear