How do people feel about the BEM naming scheme for CSS rules? It looks like overkill when used with a preprocessor but I haven't actually taken time to try it y

How do people feel about the BEM naming scheme for CSS rules? It looks like overkill when used with a preprocessor but I haven't actually taken time to try it yet. I also find myself absolutely turned off by the idea of a class that mixes underscores and dashes.