Both IMS BHU and Grant Medical College (GMC) are among the best medical colleges of India. As one of my friends studied in IMS BHU, I am familiar with the institute.
GMC is overrated. It has average infrastructure. The most important thing that diminished its popularity is the internal politics and compulsory bond by Maharashtra government. Though they have a good location, IMS BHU tops its academics and the opportunities provided to their students.