I was pleasantly surprised that he took right to it. The difficult part is finding something he'll actually drink out of it. I don't want to put milk in it yet and he won't drink plain water. I don't like the idea of giving him sugary juices but for now, juice was the best idea I could come up with.
I put 2 ounces of apple juice and 4 ounces of water in it and he seemed to like that pretty well.
Getting him to hold it is going to be the struggle. He thinks it's a lot more fun just to bang it on the table, high chair, floor, etc.
Until then, we're having fun with him trying to learn!