Terrain or mesh in my kind of game?

I am making a strategy game where the map is similar to that of civilization V but is made from actual land heightmaps. Some parts of the ground are mountainous and need more polygons but most of it is almost flat and the details will come from normalmap.
I know that the Unreal terrain system is very efficient and that each vertex of the land uses seven times less memory than a mesh vertex. But as the camera will always be the same height and always pointing down, I do not need detail levels, tessellation and even culling. My question is whether in these conditions would be better to use mesh instead of land?
I’ve done a test using a heightmap and the ground system. The result was not very good:
Terreno versus Height.jpg

If it’s not very high detail then it should be OK, might make some things easier from a gameplay programming perspective

there are more things to consider for using landscape in UEd: foliage, procedural spawning, landscape materials…many things you cant to with a static mesh as landscape geometry.
and also reconsider using real-world data for a game, as it is pretty boring and too large. either you have the assets to fill it up or come up with better content than the real nature is pretty boring in real scales.
just try that out in youre surrounding.