I've eaten at Maharani both for their lunch buffet and for dinner.
When it comes to their lunch buffet where Maharani truly excels is selection. They have the widest selection available in the Madison area which allows you to try more things -- half the point of a lunch buffet, in my opinion.
The lunch buffet has had consistently good quality food for the several times I've been there. They also do have some spicy dishes for those who are concerned about the lack of authenticity in the heat at most Indian buffets and fortunately by having more dishes available they keep service accessible to most people.
Lunch can get very crowded and that can impact water and naan basket refills.
Similarly dinner is great but can get expensive (especially if you are a naan fiend). The caliber of service increases dramatically when the lunch rush isn't on and our waiter was very attentive and helpful.
If you are looking to try as many new things as you can for lunch this is a great place to go!