We have shopped every week with Ocado since it became available in our area over 7 years ago, with an annual Delivery Pass. The range of goods is wide and pricing is acceptable. The quality of the fresh food from the Waitrose brand is superb with Ocado's own range rapidly catching up. Delivery is impeccable in our experience with excellent reliability. I wouldn't need all the fingers of one hand to count how many delayed deliveries we have had in over 7 years.
Two weaknesses Ocado need to resolve: Firstly the reliability of the packing of goods. We will go weeks or even months without an issue and suddenly a packer will crush a delicate item with a ludicrously heavy one. It is so frustrating to have a £150 delivery and then have to go to the local supermarket to replace an essential item. Secondly who are Ocado's target customers? They stock all manner of esoteric items from obscure niche producers but not some mainstream products you would expect a supermarket to have. As an example I love Murphy's Stout a very mainstream product. Ocado stock at least 10 sorts of stout and if you want a stout brewed by a craft brewery it's on the website but if you have plainer tastes and long only for good old Murphy's then bad luck. That pattern is repeated across many products and Ocado need to sort out whose supermarket of choice they want to be.