In this research paper Marek Jackubowski and a California -based team compare raster and vector segmentation approaches with ground truth. The tree height agreement was high between the two approaches as compared to ground data (r2: 0.93–0.96).
This really is impressive, to see remote sensing come this far. For many years this was the search for the holy grail for the forestry industry. I guess once in awhile you do find it, if you work hard enough and some things go your way.