I'm reading on t'internet that it needs a lot of buffing when applied - this reduces any smearing.
Yep. I apply 3 coats, with a lot of buffing, then I avoid using the wipers at all if I can help it. In my experience, once you've used the wipers for more than a few minutes, the effectiveness of the Rain-X is greatly reduced, but without the wipers it works very well indeed.
