I've been doing it every week for seven years and love online shopping, especially when I think of all the hours I've saved driving out and trekking round the supermarket, putting stuff INto the trolley, getting it OUT at he checkout, back in the trolley, out of the trolley into the boot, out of the boot at home...
People will say they prefer to choose some things themselves (meat for example) but 95% of your weekly stuff is bulky dull things like nappies, washing powder, tins etc.
You will get substitutions occasionally (but you can send them back hassle-free) and these days I find they're mostly quite sensible ones, which wasn't always true in the past.
If you live any distance from the supermarket as I do, the delivery charge is quite reasonable and you definitely save money overall if you're anything like me - shopping in person, with or without DH and DCs, regularly cost me an extra £10 or so each time because of all the impulse buys we just couldn't resist!