I remember my dad being "ambushed". On two seperate occassions, he had people he was having back-calls with. Then, one weekend, they had company. A guy who went back and forth through the Bible. I remember, because we were sitting out in the car, bored out of our skulls for 2 hours while my dad was inside in the biblical fight of his life.
He didn't say much about the specifics. Just that the guy really knew his Bible. He told everybody about the "ringer" and apparently others had run into him too. Ironically, years later, I saw this guy on TV. There was a show about JWs. He ran some Christian group. He sold books about different cults: Jehovah's Witnesses, The Way Ministries, and others. I ordered Crisis of Conscience from him and that lead me out of the JWs. Fact is, he was well rehersed on JWs and knew what to attack them on.
As far as the original question, I'm not sure either could "win". Each have their own versions of the Bible. Each has been translated according to religious biases. The Bible is not as cohesive as the JWs would have you think. Even in their own Bibles, you could show JWs things that will really confuse them if they stopped to think about them. That's kind of the key. Find something that the other person is not expecting and trip him up.
The JWs have been practiced at doing this for years. They know what the Catholics believe and how to argue against that, what the Baptists believe and how to argue against that, etc. For the most part, other religions are focused on teaching their own religion, not debunking other religions. A JW would have the upper-hand in this.
I don't give too much credit to credentials. I'm a programmer. I learned what I know now from classes in high school, from my own studies, and from playing around. I dropped out of college after only a couple of computer classes that didn't teach me anything I didn't already know. I work with people who have 4-year degrees, even masters degrees. Some of these people are clueless. Their code doesn't work or is poorly optimized. They make lots of mistakes. They just don't know what they're doing. Some schools must be too easy.
To say some religious "official" has graduated from some semenary - big deal. It doesn't mean he knows anything. A lot of people can memorize to recite something back during a test. But they cannot think or reason or really understand it for themselves. In many ways they're like JWs. Who cares about some religious version of college? JWs sit through 5 hours of meetings a week for years and years. They read and study religious articles in their books and magazines. It's probably very similar to the indoctrination at some religous college. Yet it doesn't make them any smarter or any more correct.
I think I'd go with the JW to "win" the debate, but still be utterly wrong. They're used to the debate. And I don't think either will change their mind.
