Looking at it, the grindstone is a bit redundant seeing as you can do it's exact function in your inventory crafting station but it gives you the exp back. The anvil can combine enchanted items which is really useful but the grindstone essentially is just a repeat of a preexisting function that gives you the exp of enchanted items.

The grindstone can fit into a lot more builds easier and is a more appealing block to me but the anvil out does it by trap ability and function.

Anvil Is what I am Used To, So Ya.