In my experience (studying for my masters) most interesting professors have one class that they care about (the precise field that they are working on) and the

In my experience (studying for my masters) most interesting professors have one class that they care about (the precise field that they are working on) and the rest could be taught by anyone else. Being a good researcher is not correlated to being a good lecturer. Even at graduate-level I'd pick someone who is good a teaching over the absolute #1 in the field 9 times out of 10.