I can't say! It's been so stinking hot and humid lately that I haven't been driving around with the windows down - AC on high!since you've now had a direct A/B experience: do you find the wind deflectors make driving with the windows down much quieter?
At any rate, they don't help much (enough?) with the moving wind noise for me. I haven't driven above 35-40 MPH with the windows down since I got a vehicle with AC in it. The noise and buffeting on my ears drive me crazy, can't stand it!
Only reason I got the deflectors was to leave the windows down a bit while it's raining - for which they are very effective.