SimCity-like Terrain Editing: Marching Cubes vs Unity Terrain

Hi! I'm working at a game where I would like real-time terrain editing. The game is supposed to be a kind of a city builder.

I'm working right now with Marching Cubes, but I'm having some problems updating the mesh (holes between chunks etc) when editing. All I really need to do is lower/raise terrain (and add texture depending on height and the slope of the normal).

Is it possible to do this with Unity Terrain? (ex. setHeightMap?) I really like the possibilities with procedural generation, but would it be easier to just use my voxel-data to produce a heightmap for a Unity Terrain? Is real-time editing of Unity Terrain efficient?

I've never really gotten into editing terrains in Unity, so I don't know if there is even any point to using Marching Cubes instead of the built in terrain? How does the terrain in Unity compare to a voxel-based terrain in things like speed, editing and procedural generation?