Very good range of stock - much wider than a "normal" supermarket.
Very rare to not get what you order.
Drivers invariably pleasant.
The "offers on your favourites" feature is useful.
Sure, you need to be careful that offers are really a good deal - so what's new? But it's easier to do this online than in a physical shop.
I'd like more information about provenance so I don't buy stupid air freighted goods,, goods from companies (yes, ownership by the likes of Kraft or Nestle is there in the info, but I'd like a facility to exclude these multinationals) or countries I don't wish to support, or contribute to destroying the water table in Peru, for instance.
I've been using them for a good few years and don't plan to change.