The hostel facilities are excellent for the PG students in medical and surgical branches. Many of my friends in AIIMS and PGI have visited NIMHANS and claimed its hostel facilities to be better than their hostels. The hostels are well-maintained and hygiene is given utmost importance. Additionally, there are family rooms available on the basis of seniority.
However, the non-medical trainees don’t get very good hostel facilities as their buildings are old and retarded. Most of the old academic buildings have been transformed into hostels for non-medical trainees so you should keep your expectations low if you are one.