Well, to begin with, nobody can do any research with a mentalistic outlook. It has nothing to do with any science. That's out of the question. How much leeway do you want in the selection of problems. Well, my answer to that would be that the interbehavioral view has a larger scope.
Language is a bigger thing than verbal behavior.
As I tried to indicate, I would offer as a final statement the advice that you should, if you're interested, study the two views carefully and come to your own conclusions. It's no good in any science to be told what is better and what is worse. That doesn't mean anything. I speak now as any scientist would. It's not going to be anything absolute.