Rather than looking for the perks of doing an MBBS from AIIMS, you should be asking what would you be losing if you are unable to make it into AIIMS and if that loss is worth worrying about. In a medical college, most of your UG time goes into exams and studies and you are left with no time to analyze where your interest lies - Medicine or no medicine / USMLE or AIPG
AIIMS does not have campus selections and all doctors are paid equally in the beginning whether you belong to an AIIMS or not. The medical field does not value brand names but it's our personal efforts that actually matter.