Things become clearer when you consider the 1985 Anti defection law.
One possible answer is the Tenth Schedule of the Indian Constitution. Popularly known as the Anti-Defection Law, the Tenth Schedule was written into the Constitution by the government of Rajiv Gandhi in 1985. The schedule mandates the disqualification from parliament of any member who votes against his party’s whip. Supported by many Indians, this law was originally conceived to control rampant defections by members of India’s parliament and state assemblies in order to save or bring down governments.With the backbencher debate culture lacking, it doesn't matter whether your MP is the most honourable or has the best work ethic, that will only affect in limiting the corruption under his wing. Know that while it does come under their jurisdiction, MLAs and municipal councils are more directly responsible for the administrative state of affairs in each constituency. The role of the MP(as I see it) is more of a representative in making national policies and bargaining for a share of pie at the national table.
Therefore, I believe that one should vote for the party and not the MP. Ofcourse, there are exceptions. If you are given a choice between a criminal from a party whose ideology you believe in, but an honest politician from a party whose views you may not agree with, you should vote to punish the party that put up a criminal. This will ensure enough feedback to the system that criminals may not be fielded in the future. (Tytler is a case in point)