I'm 6'3" so I bought the Cee Bailey +7 windscreen.
I'm pretty happy with it. On most rides I only have to raise it half way, which keeps the top lip below my line of sight but still reduces the helmet noise and buffetting considerably.
The windscreen really earns its keep in foul weather and winter conditions. I ride totally protected while staying nice and clean.
The only thing I wish was better was its rain-shedding ability. Water does tend to cling a bit more than I would like and the most popular screen polishes don't make any difference. I think the lexan attracts and holds water.
I'd give the Cee-Bailey 8.5 out of 10.