Generally, I am very impressed with the service from Ocado. The range of products is excellent and it is not often that things are out of stock. It is rare that items are substituted, unlike other supermarket online deliveries.
The deliveries are always on time, the drivers are without exception polite and helpful.
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My only criticism is that delicate items like eggs or bags of flour don't seem adequately protected, eggs cracked and flour age with holes in.
After using Ocado, I would not use any other online supermarket deliveries.