My brother, who had taken four different month long treks in Nepal (twice)l, Pakistan (glacier fields) and Andes mountains swears by Nikwax. It was recommended to him by the various guides and has never failed him.

I think that is a good testimonial for Nikwax.

"The whole problem with the world is that fools & fanatics are always so certain of themselves, and wiser people so full of doubt" Bertrand Russell