Hmm...
I'm not a fan of hex. Yeah, yeah, it's ok in the open, but it's absolute murder when mapping a dungeon, double the headache if it is complex. Then you have to go and map out your own area templates for every single spell area there is (a 10' radius, a 20', 30', 40', 50', 60', cones, etc.), since all of htese are based on the grid system.
In short, I pick convenience. The trade off in reality isn't worth the extra time, IMO, especially since the DnD combat system isn't exactly life like.