Been to Vishal Mega Mart and found that its just another big size retail store. Although you do find some good deals that you wont find at your neighbourhood grocers but all in all your grocery bill here would be more or less same as the one from your neighbourhood shop.
The good thing is that you will get a TIN numbered bill for every purchase so you are sure that the VAT component of your payment goes to the government. A specific incident I noticed - I bought some stuff and found out later that VMM had charged me Rs. 25 for an item that had Rs. 20 as the marked MRP. that Rs. 20 mark had been masked by VMMs own barcode sticker.
Now I see this as something very serious as it puts a question on the strategy of this organisation. For now: my advise would be - be careful about MRP as you dont know how many products are being sold at this store like this.
Will keep the forum posted once I have discussed this issue with the store management