I tried the Terrain Awareness this morning and it worked well. I tried it on a site that had moderate elevation change to be safe, but I was at the high point and could tell that the drone was raising and lowering accordingly. One suggestion would be to make sure that you have at least a 20ft buffer as this is the deviation that you could get with the combined accuracies of the drone and the DEM that was used for the terrain. This is mostly important for those of you that like to fly at very low altitudes. I typically fly at 200ft and one of the first things I do on a new site is go find the tallest obstruction in the flight path and make sure I have 150ft of clearance. This also ensures that I get good overlaps in those areas.
With this addition I am closing this thread as it is no longer relevant. Please visit the new Terrain Awareness thread.