Tandoori resturent markets to the puritans who love the opulence of exotic Mughlai-style; whereas Barbeque Nation (BQ) is a modern contemporary North-Indian bbq-styled.
Frankly, I have had better and richer Mughai food in North India so Tandoori was a let down. I hear the "dal makhani" is milder and tasty but I only like yellow lentil so I didn't have the chance to taste it. This is a place for rich white people or NRIs who have not travelled to North India and want to try the food here. I think even the staff knows that and behaves accordingly. For this price that we pay, I expect the food to be more memorable. Maybe it is one of those places that use to be good.
On the other hand I found BQ to be better; and I wasn't even interested to try their main course. BQ is an all-you-can-eat buffer and the highlight of their food is their bbq starters. Nobody in their right mind goes there for the main course. Another thing I liked was that the staff were very courteous and attentive. I loved the pomegranate and passion fruit mocktail.
Those both paces are know for their "sheek kababs", I do not eat sheep meat so that is something I have nothing to say. I am a slow eater so its a dash to finish my food before it gets cold sitting in these AC restaurants.