I quit using RainX on my daily driver. The benefits only are apparent at high speed. Yes, I used to have to make weekly 200 mile trips and I could turn the wipers off, it beaded the water so well. But, as others have mentioned, windshield wiper chatter, sensor issue, and things like that have now steered me away from it.
Ultimately, it's a personal choice. If you drive long distances at high speed in the rain, there is a definite benefit.
Otherwise, I'll take what the engineers gave me.