The juddering after application has nothing to do with who applied it or the method. It's apparently down to the shape of the screen on the mk7 and it also happens on A3s too. My detailer won't apply one of the gtechnic products to any mk7 golf windscreen, can't remember which one though. As for standard wipers being rubbish that's a load of nonsense too. I've got the originals on mine and after 10k miles they still work perfectly!