Bigbasket is one of the oldest and the best online grocer. I have tried other companies like peppertap and ZopNow mainly for the hefty discounts they have been giving lately but I somehow felt BigBasket has a better service taking quality of the products into consideration.
But the worst aspect of BigBasket is that they take about 24 hours to deliver whereas many of its peers are delivering in not more than 2-3 hours. I made around 40 orders on BigBasket and the delivery was always in accordance to the time slots given by them and I never faced any problems like wrong products being delivered or old products nearing their expiry being delivered which I sometimes faced when I ordered products on Peppertap.