Primary use will be youth baseball and football, and with the 80-200 candids. In order to slide the 80-200 past she who must be obeyed, I will probably have to give up the 180 f2.8 (which I love) so that is a big negative for me. As far as the 300 f4, the only negative I see is the reportedly slow focus. In any event, thoughts on the relative merits of each? I am a large fellow, so doubt that the weight of the 80-200 will be an issue.