Every actor has limitations. Akshay is better at comedy than others on the list, Shah Rukh does romance well. Whereas, Salman rules masala entertainers. Whereas Aamir Khan is known for intellectually stimulating content.
If I had to rank them:
1) Shah Rukh Khan (I think he was phenomenal in Fan. I would forget Gaurav is portrayed by SRK!)
2) Akshay Kumar (He's done many films I've loved.)
3) Salman Khan
4) Aamir Khan
5) Hrithik Roshan (I have never watched a Hrithik Roshan film. However, if his performance in K3G was anything to go by, he was strictly below average.)
50