This site lists many current and past McMaster professors and how people rate them based on how easy their classes were, how helpful they were and everything else.
Some of your profs won't be on there, but I found 95% of mine on there. And to prove to you that some of the explanations people had were legit, the profs that I've had before, such as Holmes & Mercier, people were dead on their conclusions after having the prof.
http://www.ratemyprofessors. com/Se...jsp?sid =1440
Please keep in mind though that everyone is different and will have a different perspective of each prof.