Groceries delivered in one hour

Instacart is an on-demand food delivery network for people who don't want to be grocery shopping right now. They've just been valued at $4.2B and are Y Combinator's third largest portfolio company to date.

Would you recommend this product?
1 Review5.0/5
I've been using this for a few weeks now, basically a more affordable version of Peapod.
$200MM –– damn.
$4.2B valuation for a service supermarkets already offer? Am I missing something here?
I use Cornershop here in Mexico (Monterrey), it works like a charm and with the scheduling of order time one can get the groceries delivered just after arriving home from work or similar. We use it once or twice a month and once a month we go by the store for good old times sake.
I have tried using Instacart several times but I dont think this app has solved grocery delivery completely. I don't like the fact that the mark ups they have are hidden. How would I know how much extra I am paying than the store? I want to see my receipt and get an idea how much extra I am paying