Btw, some say Dr Berger, some say Berger, this should be Rabbi Dr Berger, whether you disagree with his opinions or never read his books.
I did not learn his positions on Chassidut, but I had an interesting interaction with him many years ago – he made an oral presentation that was pretty strict on how to relate to another religion. I asked him on one articular nekuda where his presentation explicitly disagreed with a sefer he co-authored. He replied that his position is what he said and that particular chapter was written by the co-author and they could not come to an agreement on the issue. I guess, a good argument for “oral learning”.