Out of all the "international branded" properties in DEL, the Marriott has consistently the lowest rates. It's sort of out of the way, being in the Saket/S. Delhi section .... but you need a car to really see DEL anyway.
The lounge is decent and the hotel is relatively new -- like 4-5 years only (at least as a Marriott). The only complaint I have is that on certain days and at certain hours getting a taxi there may require a wait.