Well each and every course has advantage and disadvantage in some respect. Its really very difficult to say which course is best for M.Sc among - Biotechnology / Biochemistry / Lifescience as three of them are good and have their own priorities

I will suggest you to go for that course in which you are interested so that whever you choose you can give your 100 %

Once you select a particular stream you should be sure that it is the best for you. Changing streams is not advisable.

According to my opinion you should go for biochemistry stream. But choosing subject is totally your choice.

Career after M.Sc in Biochemistry

There are scores of private firms in India that requires Biochemists. Students who have finished their postgraduation in this subject also stand a chance of getting jobs with firms that conduct research in-

Pharmacogenomics
Gene therapy or Genetic testing
Drug research and testing
Food quality testing, etc

Other major employers in the public sector include--
Agriculture companies/Irrigation
Water authority
Social welfare board
Drug testing centers
Government laboratories
Civil amenities, etc