I was a JW for 23 years. I read the Trinity brochure on countless occasions. Once I left, and began to research the Trinity and historical Christianity, it was immediately obvious that Watchtower distorts what the doctrine really is.
In short, they define the Trinity in such a ridiculous manner, that even non-JWs at the door will reject it. (Ironically, the JW at the door thinks they've proven the Trinity false. What the JW has actually done is prove that they don't understand the doctrine.)
My biggest problem with WT and the Trinity is this: They use it as a litmus test to prove that any religion believing it is "False". Moreover, they fail to tell their followers that JW theology on this subject is from Arius, from 300 AD.
Walter Martin once said that when a JW shows up on your door, they're preaching a concept of God that has been perfected over the past 1700 years. C.T. Russell didn't invent it.
I have spoken with many "mainstream" Christians. Few of them believe strict adherance to "The Trinity" is a central part of worship. What they DO insist is that Jesus is Divine, and any attempt to make him just a perfect man, just a 2nd Adam are wrong. They are monotheistic. The Father and the Son are two different persons, but they are both "God".