My wife and I use it quite often... Mostly for 'big shopping' You know, for parties, cookouts, or just restocking lots of stuff or lots of bulky items. We actually try to build up 'alot' of stuff and then send in the order... Its so nice that they bring the groceries upstairs (bi-level home). For us the delivery charge (and we tip) is well worth the time NOT spent shopping.
We do online order our boars-head cold-cuts (we can even specify sliced thin) but we usually go to the store for picking out cuts of meat or chicken parts or seafood etc.
We also use it in another great way...
My wife's dad is now a widow and is loosing his vision (but wants to remain independent as long as he can) so once a month we do a 'restocking' of his groceries via peapod... Mostly the 'staples' plus I sneak in a box of Entenmann's chocolate doughnuts or cake when she's not lookin...
It sure is a godsend since he lives in the next state over and 'popping over' constitutes a 2 or 3 hour 1 way trip.
Reason I'm posting to this thread is cause I was thinking how cool it would be to have a native iPhone app to order all my stuff but I think Apple developer regs might not allow it.
D