The look of a material greatly depends on lighting and rendersettings as well as the diverse settings of the material themselves, so even a downloaded shader doesn't necesarilly look good in your scene and I figured as much ( that you had some experience), but it doesn't matter, the endresult is the only thing that counts and it looks pretty good. And there is always something that could be better or improved no matter at what level you are, just close this project off and go to the next one and look at it again in a year or two