Mahal has a good mixture of different cuisines from around India on offer, from the grilled and tandoori meats of more Northern cuisine to veg and fish dishes from the South. The food is all good quality, although I found it a bit toned down as much Indian food in London has seemed to be.
Still, the portions are generous and the prices are modest enough. They have Indian beers on offer, although I was kind of hoping they'd have some Indian wines as well (there are in fact a few acceptable Indian wines coming out of Maharashtra and Karnataka).
As has been noted, this place is especially suited for take out, or at least that's how I've used it before. The staff are really warm and friendly, however, and recognize regular customers which is nice. They also have a restaurant in Edgware Road