Rodinal is great stuff, and it has its own particular characteristics, just like any other developer. If you test it carefully and use it consistently, you will get good results. I find it to be a very clean, low-fog developer in normal use. It is a bit touchy in that it will quickly overdevelop highlights if you don't mind your time, temperature and agitation. So will any other developer used inconsistently. Read the highlighted articles posted above. The low-fog characteristics will disappear if you use it to push a high-speed film like Tri-X to 1600, however. Normal use and gentle agitation are key.