For most of us, riding behind a properly designed tall windscreen is the difference between riding for an hour and riding for six. The screen redirects the heavy wind blast away from and around the rider so your body no longer has to fight to maintain its position. The feeling is more like standing into the wind on a breezy day than trying to stand against hurricane force winds. This relieves the muscle soreness associated with this constant struggle. Your neck, back, abdominals, and arms will thank you.
Its also much warmer if you ride in the cold and drier if you ride in the rain for the same reasons. Wind chill can be reduced considerably. Instead of dressing to look like Frosty the snowman, you can reduce your clothing to just a thermal suit or well designed wind proofed coat and regular clothing on most days.
Of all the accessories I've invested in to make my CTX the perfect companion for everyday riding year round, the Ceebailey windscreen ranks #1 in my book. It was a cheap investment for the comfort and protection it brings to fold.