Hello, I had similar dilema recently, and decided to buy x-t1 because the fact that it has weather-sealed body (dust, splash, freeze proof down to -10°C), larger viewfinder than x-t20, more manual controls with a separate ISO dial and can be equipped with grip with extra battery.
I think that x-t20 will be better for shooting fast moving subjects - as it has more af points. If you like touchscreens it also coul be an advantage.