Sanjay Manjrekar: better than the others by some margin. The most level headed and unbiased commentator from the subcontinent.
Harsha Bhogle: General commentary is rather good. he makes up for his lack of cricketing pedigree with stats. havent heard him talk about actual batting and bowling techniques.
Ramiz Raja: Most unimaginative commentators of all. Repeats his "favourite" words over and over again.