I see promise in Network Topology Mapper, but it's not quite "there" yet. One area that I think holds great promise is in the area of being able to use NTM maps in Network Performance Monitor. Presently, NTM maps have to be imported into Network Atlas before they can be used by NPM. This makes the maps into static views.
I think it would be extremely useful for NTM maps to be able to be dynamically updated in NPM. If nodes detected by NTM exist in NPM, then have them automatically linked. IMO, this would greatly enhance both applications.