Microsoft visits NIT Trichy every year to look for students who can offer internships. The company visits during the 7th semester for the placement season. If we go by that logic, Microsoft hires interns who have just completed their second year and are about to start their fifth semester. The position of an intern is usually open to the students who are pursuing ECE and CSE.
Coming to the experience one gains, it varies from person to person. In the past, interns have turned down PPO offers from Microsoft.