Greetings,

advantages:

- the AIIMS tag and reputation for life

- better infrastructure and possibly better facilities

- fees difference

disadvantages:

- faculty not as well established

- not much in the name of student culture in new colleges

- Not many great mentors, good opportunities to learn

- probably a very new research culture

If you want to go for better academics and better mentors, go for an already well established college, if you want the AIIMS repute, better facilities for the next 5 years and an outside experience for once then go for the new college.

good luck