I use a grid, but am trying to move to gridless battlemap. Currently mainly 2D, but would like to use 3D representations because I think it greatly enhances players' (chances for) tactical thinking. To me, relying solely on verbal descriptions seems to result in either an impoverished* environment or really lengthy descriptions, and to disadvantage players who do not visualize well. (However, it also seems clear that for some groups those issues are not big concerns.)
I am confused by people saying there are encounters in which there is "nothing interesting" about the environment as if that was something that occurred naturally. Unless your setting is a featureless plain, there's always going to be something that the PCs might find useful if only they knew that it was there.
*Ok, "impoverished" might not be a really good word choice, since many DMs can provide, do provide, and pride themselves on providing a lot of nice evocative detail in their environmental descriptions. It's just that it is generally going to narrow in on what the DM thinks is interesting, whereas the construction of a concrete visual representation generally forces the inclusion of a good deal of additional detail that the DM may consider random or uninteresting, but which the PCs might find useful. Of course, it is still a matter of degree - even a lavish 3D construction will still omit many possibly interesting details. Also, I'm not suggesting that maps or constructions can replace a good verbal description - they're just a highly valuable (IMO) complement.