Personally, my esteem for the Fourth Way was not harmed at all. Seeing Gurdjieff as a man (albeit a remarkable one) didn't diminish the value of the teachings. In fact, I've found myself returning to the Fourth Way (primarily through Maurice Nicoll) with more interest than I've had in a while.

I found Gurdjieff when I was a teen. He was one of my first initiations into the world of esoteric spirituality, and the Fourth Way was the first school I studied in a serious and dedicated way, but over the years, I found myself exploring other ways of thinking. I've returned with a passion to the Fourth Way, and reading Churton's book hasn't diminished at all how profound the teachings are to me.

That's just my take on it. Best of luck to you on your path of return :)