Having owned a detail business I used many products over the years. My best success was using Meguiar's concentrated glass cleaner. I bought it by the gallon. The main problem people face with cleaning windows is streaking. The solution is go easy on the concentrate when mixing with water. I found that a 10:1 ratio works best but, you'll have to experiment. One more thing... use two towels, one for initial wiping and one for drying. Micro fiber is your best bet. Finally, you can find this cleaner in automotive paint stores, they generally have detail supplies. It mixes to a blue color and actually smells good.
