ocado are great. Nice little touches like buy back of carrier bags, decent length dates and a nice receipt which separates things by their use by date (good to put up on the fridge)
This is my only criticism of Sainsbury’s. It’s all too easy to shove everything in the fridge and not check the dates. They only advise if there’s a short date within 24 hours.
Otherwise Sainsbury’s online service is excellent. It definitely saves money as I’m forced to plan meals and make fewer impulse buys.