To be honest assuming we are playing in a situation where I need them, I can't tell the difference between my ribbonned discs and those without. I have a few pairs of discs with only 1 ribbonned and at times will throw the one w/o ribbon. The boots, bad footing, and layers make much more of in impact.
But....what I have noticed is spending time searching for discs and worrying that I'll lose one does have an impact. So, if there is more than ~6" of snow I'm generally throwing a ribboned disc.
I agree. While there must be some impact on the flight, it is pretty negligible and the isn't very obvious.
The pros outweigh the cons. Give the ribbons a shot.
Note: I have had discs hit the snow with a lot of spin and the ribbon got wound up and sucked away. It's not foolproof at leaving a tail out.