I've been using the Rain-X solution since the 90s and love the stuff. With a sloping windshield, the rain blows right off if you're traveling at a reasonable speed. Danger is, visibility is so good, you can overdrive your tires in the rain.
Wifey, however does not like it. She drives a Wrangler, and the Wrangler has a steeper windshield angle than most vehicles and the water just tends to lay there obscuring vision.
I've never tried the w/s/w fluid. Heard that it stains the paint, so haven't risked it. No need to. The traditional Rain-X is so easy to apply. Invest about 10 minutes a couple times a year and you're good to go.
Oh, if you follow the directions, you should wet the windshield after treating it, and wipe it down with a paper towel. I don't experience any night visibility problems.