Those below have more discernable holes, less flattering records in varying conditions, less consistency. The 3 at the top and possibly the two after have more bullet proof records, not showing disparities between home and away and not withering against the biggest challenges. If you can accomplish both, you deserve be in a separate category. Plus he could do it all, was accurate, could swing the ball and could go all day if required.
Except you are wrong. Except for Marshall, no pacer has a bulletproof record. We are all just picky in whose record we want to upgrade and downgrade because of lazy selective analysis. Each of their cases is much more debatable.
Hadlee never proved himself in the WI, and has not much in the SC for us to judge him.
McGrath is dodgy in Pak and SL and not great against SA.
Steyn had a high home/away disparity, was expensive in Aus, Eng, SL and UAE, which we all ignore.
Imran had a high home/away disparity too and high averages which we don't ignore.
Ambrose doesn't have much to judge in the SC, never played in India, and had major penetration issues outside Aus and Eng.
If I wanted to pick a bowler in the SC, I think McGrath, Hadlee and Ambrose have certain questionmarks. Steyn bizarrely gets credit for flat pitch era success despite playing at home on greentops while Imran doesnt despite playing on pancakes at home. Ambrose tore apart the best side in the world in Australia, Hadlee failed to do so in WI.
Point being, outside of Marshall, it isn't clear, we may have our preferences but it all comes down to selective criteria, but it really should be him as clear best and the rest.