A good Ettore squeegee is the only way to clean glass--fast and streak free. I like crystal clear glass on our house and vehicles and it makes it easy to get good photos through the windows.
I recently discovered RainX water repellent and have used it on all our vehicle windows and windshield wipers. It's amazing how rain water beads up and slides off. When the weather warms up I'm going to try it on some of the house view windows.