I honestly have nothing bad to say about the book study conductors I had.
I had 2 personal book study conductors, and both truly believe the stuff they taught. It was only later when the second book study conductor became an Elder did he become an ass. (I don't know what it is about the local Kingdom Hall that turns good men into ass-holes when they become Elders.)
Regarding the group book study conductors, each had their strong points and weaknesses. As long as they stayed out of their "Elder mode" they were pretty good people.
"Hand me that whiskey, I need to consult the spirit."--J.F. Rutherford.