The Holiday Inn Express within Terminal 3 is perfectly acceptable for international arrivals connecting onto domestic flights from Terminal 3 and my associates think the service is very good at it. And the views of the tarmac when having the included breakfast aren't bad from it. Due to the T3 departure requirement to use the hotel, that tends to favor the use of some airlines, Air India and Vistara in particular.

But this HIX goes for quite a premium in rates over what the other hotels in the area cost if willing to exit the terminal building for overnight stays.

The HIX T3 on Level 5 is what we use for those who are concerned about DEL safety/security during overnight stays on transit layovers at DEL.