They are fantastic. I cut down my windshield and use a 3/4 helmet and the buffeting was really bad when I got over 60 or 70mph. I thought it was because of the lower windshield. It wasn't. I put the wind deflectors on no more buffeting. A great purchase.
I first found about them over 10 years ago when I road to Sturgis from Pgh ( 4k solo first trip) The wind kicked the crap out of my face and when hanging out at Rapid City HD got to talking about the situation with a guy who had a lot more miles under his belt that i did. He recommended them and he was right. Huge difference for me whether on a Heritage of electra glide. Just got an 09 Ultra and put my 05 EGC deflectors on.
I'd rate these as one of the the best dollar for dollar comfort adds I've ever done.
IMHO.