It has definitely made a difference for me. I got the 701 without a screen and always felt like I'd have to hang on a bit too much at highway speeds, which is no longer the case with the screen. I still cop a bit of wind to the face, but it's a big improvement in terms of comfort.
It is just a cheap $10 screen off AliExpress but I am really happy with it until I decide to bite the bullet and get a rally tower.
AAAAAAAAAAAAAAAAAAAAAAAAAA