If you join Dr RMLIMS instead of KGMU, Lucknow, you would be missing the opportunity to be a part of one of the top 5 medical colleges of India. You would miss the Georgian tag. You will miss the rich legacy attached to the institute. You would miss campus life at a huge college. You will miss the amazing infrastructure no use. RMLIMS is an excellent medical college but it is still way behind KGMC by a significant margin. It has recently launched the UG course i.e. MBBS so it will take time to establish itself.
All in all, KGMC is the better option at least as of now.