Nightmare. I tried it because there was a £10 free start up offer. The service was hopeless. Some days not at all or left in the street outside other houses, but not outside their door - literally in the street, even though I phoned up and said we are the only house in the street with scaffolding on it! In the end I stopped all deliveries as too frustrating.
I have also used it for a number of years and have found it very convenient, particularly if you need to change a delivery or ask for an additional delivery.
The service probably depends on your location. I think my one is the "fastest milkman in the west". He flashes past, in as much as a milk float can speed. I gave them many chances to improve but it didnt happen.