Steyn is better bowler than Asif because,
- Steyn is not just quick as many guys said above, perhaps they concentrate more on Asif than Steyn. Steyn takes wickets with Swing and benefits a bit from pace. Asif is somewhat the same but has little bit less pace.
- Asif relies on Drugs to bowl, though he plays for Delhi, i still don't support cheats. Most of the outstanding bowling he did was under the influence of drugs he would have taken. Also whenever there is test done on him, he comes out to be culprit almost everytime.
- Steyn has a better Bowling Strike rate . .perhaps among top five in all time list.
- Main Point : Whenever a new bowler comes into the international scene when not many international batsme n have played him. It is easier to get wickets even world class wickets. There have been many like Bond, Asif, recently Mendis, etc. But what is more important is how does the bowler perform when everyone knows him and how he bowls. This is the time when it gets difficult for the bowler. So a bowler whose career starts slow and rises gradually is a better bowler than who starts glamorously and then dips down. And here Steyn is a better bowler than Asif.
My Vote goes to Steyn, after watching extensively both the bowlers