Bart Ehrman is a is a New Testament scholar and an expert on early Christianity, but I disagree with him about the part that Paul did not write some of those letter in the NT, and I disagree with him on many other things. He used to be a Christian and now he claims to be agnostic. Many New Testament scholars and experts on early Christianity disagree with him too. But he knows his stuff well and if he continues his research, I wouldn't be surprised if he eventually ends up coming back to Christianity.
Well, a researcher in any field should keep his personal feelings and opinions and faith out of his research, to the largest extent possible.
He only points to the evidence. I'm no Biblical scholar so I have to go by what the experts say. The next time I get around to reading a book about the scriptures, I'm picking one by someone from a different vantage point than Ehrman.
As long as it's about looking at the evidence, it should be a fun discussion