Too much risk of them killing it with little warning.
I use it for shopping list with my wife. It is awesome for that one feature.
Have you tried wunderlist? My partner and I have a shared shopping list that we both can populate and finish items from—offers a bit more structure and to-do type item features than Keep.
I liked wunderlist but we have a different note for each store with a check box. Nothing beats the keep for shopping list for us. Simple and easy