Hello Sara, it is all rather subjective and what suits one doesn't always suit another. I would suggest you register with all of them (not necessarily at the same time) and give them all a trial. I have come down to Sainsburys for the most efficient and best for me. Tesco has the best website, Asda are the cheapest and Waitrose are the dearest. Tesco give you a two hour delivery slot and I think it is them that offer you �10 if they are late - but the drivers often argue that they were there on time but had to do some paperwork - so it doesn't always work. Sainsburys give you a one hour slot, as does Asda. The costs are pretty standard, about �6 for weekend and between �3 and �4 for midweek. Some give you free delivery if you spend over �100 but I haven't so far been able to achieve that. :)