1) The biggest issue is the constant non-availability of products. If you order 10 items from the store you can be sure that at least two items will not be delivered to you and will follow the next day. So that means you have to waste two or three days just waiting for the delivery.
2) In recent times they fail to even come as per their scheduled delivery slot. A recent example being a delivery I had scheduled for between 7-9 am which finally reached me at 10.30 am and that too only after a call to their customer support. Otherwise I don’t know what time it would have reached me.