if u use a microscope, u will find that our car winscreen have lots of bullet holes due to stone chips which we cant see by our eyes.
if u apply rain-x for long term, those liquid will clog the hole and yur winscreen surface will be uneven. it will leave a layer of hard foamming thing and some guy believe it is enough to cut yur rubber blade. did u guys notice the cap of the rain-x will leave some kind of sharp crystal thing?
there are so many brand of silicon wiper around in the market ranging from rm 9.90 to 200.00
for me i am using piaa silicon wiper for 3 year without changing the blade and it works like new, but the downside is it will get stolen everywhere by those chipskate.