This debate has been ongoing since the creation of the first graphite shaft. What are the advantages to using graphite? Why do many people insist on playing with steel? Which is better for you?
I would like to first make two general recommendations. Better players should always use steel and golfers who are lacking in swing speed should use graphite. Steel shafts tend to be heavier than their graphite counterparts and this can effect the swing speed of any golfer. This tends to suggest that a lighter shaft for the slower swinging player will help them increase their swing speed. Finally, the lower handicap players are usually able to produce adequate swing speed not to have to worry about the weight of their clubs.
The steel shaft does however tend to produce better feedback into the golfers hands during impact of the ball. This can be good or bad. For the better player who needs to feel the ball and where it has stuck the club face the steel shaft will help. This is different for the golfers who miss hit the ball often. Because the steel shaft can send more vibrations up the length of the club, it may not be wise to use steel if you rarely hit the sweet spot. Graphite tends to provide less vibrations up into the hands, which can be good if you don't want to feel the sting of a poor shot, but bad if you are hoping to feel the ball go slightly off the heel or toe of the club, Especially in cooler weather.