As both the colleges are good, but as per Careers360 rating AIIMS Delhi is better than B J Medical College as AIIMS Delhi has got AAAAA rating which says this is an outstanding college overall whereas BJMC got AAAA which means this is a good option to pursue MBBS course from there. So if you get chance to get admission in AIIMS Delhi then you should go ahead wth the same and if not then BJMC is also there as a secondary option.

To check the rating and ranking in detail of both the colleges, you can go through the below links-

https://medicine.careers360.com/colleges/b-j-medical-college-ahmedabad

https://medicine.careers360.com/colleges/all-india-institute-of-medical-sciences-new-delhi

Good Luck!!!