What is your preferred way to control KI? The Xbox One D-pad, the analog stick, or a fight stick?

I personally use a fight stick for every fighting game I play, including KI (I use a CronusMax adapter and a 360 arcade stick). Years of playing older games in arcades have made it the obvious choice for me. However, if there's a fighting game that needs an arcade stick the least, I'd say it's Killer Instinct. There are no systems like plinking or pianoing that really benefit from an arcade stick layout, and there are no complex joystick motions either, so it's a game that can be easily learned using just a controller if you have no established preference.