I love the series, there is a ton of information available given in a fairly clear and concise manner. But season 21 and the addition of Adam Richman killed it for me. It became more if a sitcom one they tried to integrate having a host actually asking questions which could have been filled with more information as statements removing a ton of extraneous fluff.
So for now I give it 9 stars for everything up till season 20 and season 21 isn't worth a single star.
There are sometimes flaws in the statements made but they are generally pretty close to the truth and the information given can help open the minds of the people watching so that they are spurred into gaining even more information. I know I have learned more from this show than multiple years of public schooling.