I would like to share my personal view on this as a BPO employee (TEAM LEAD), not as HR. Whenever we are trying for a job, we used to go for both Monster and Naukri. Most organizations update their job postings on both portals in different categories. (Monster - Used by more consultancies)
If our search criteria do not match on Naukri, then we will go to Monster. However, we are confident that we will find a relevant job for our search on either Naukri or Monster. LinkedIn is good for top-level searches like Managers and above, but not suitable for executive-level job searches.
If you want to stay directly in touch with employees, then use both platforms and communicate directly with people instead of using any consultancy. This is my personal view as I have recently been searching for a job in healthcare BPO, and it is based on my personal experience.
Thank you