i've just tried the free version! it is ok but there are some bugs as it disapear from time to time from the store... i'm still trying it
THE LIVING MODE
It is a basic order delivery estimate app which says "delivered within X days" but if your item sells out and you allow backorders/preorders, this will not work.
Great potential since they said that they are working on a solution on this. However, I really do think that support can be improved.
Looking forward to your new features that will include that function.