Depends on the kitchen.

What PPF said. I have tile to the ceiling because that is what the kitchen called for; in other scenarios it would be overkill or look bad.

You need a clear stopping point or it will look bad. You don't want to tile to the ceiling and just leave an edge hanging there, which is why is usually looks best on a singular wall with boxed-in borders which creates the natural stopping point. Like this:

Yes, No, Maybe. Context is key. Post up pics of your kitchen.

I did it for my window/sink wall with a u-shaped kitchen. It made sense for that kitchen layout ... it might not make sense for your own kitchen layout.