I sometime use Ocado in the UK, and it's 'OK' but it's certainly not at the cheap end of the market. I more often use a traditional supermarkets home delivery service where it's manually picked; those supermarkets have the advantage of having very little infrastructure overhead in the picking - they mostly use their existing stores and pick at quiet times/over night. Ocado has to run entire warehouses just for this task. Ocado can only work with packed goods - not weighed vegetables for example - which the hand pickers in store can do, albeit whether they do it well is down to luck and the mood of the picker.