I'm considering replacing my North Face gortex jacket as it's starting to get a bit tatty,  some of the zips are breaking,etc.

I've seen quite a few [paramo jackets](http://www.paramo.co.uk/en-gb/index.php) about. I'm presuming they're quite good as they are the jackets I see a lot of mountain rescue members and mountain guides wearing. 

A mentioned this to a friend and he said, "they're the marmite of mountain equipment, some people love them, others hate them" but didn't elaborate further. 

So what does a paramo jacket do that's different to gortex? What are the advantages and disadvantages of each?