Bob Dylan as a song writer just by sheer volume of successful tracks penned and used by others. As a singer Van Morrison could be better for me but it depends on what mood he is in on any given day. Of the three times I have seen Van Morrison over the years you never know what to expect from his mood. Once when I saw him he was clearly not in a good mood. Played for barely 45 minutes as I recall. Didnt speak, didnt interact apart from a few grunted swear words no effort just going through the motions then left no encore thats your lot. Yet next time he was charm itself and went on and on with encores and rapport with the audience. Strange man.