On the whole my children get along with each other remarkably well. I'm not saying they never fight or get mad, because heaven knows they do, but they can spend long periods of time together and they do seem to enjoy each other's company.
I snapped this photo of them just last week at Rebecca's soccer practice. Jake had brought his DS and the three of them were peacefully sitting together. They were able to entertain each other for the whole hour with minimal fussing.