I've been using an MRA streetshield and really like it.
Small and out of the way for off-roading, and it keeps the windblast off my chest for sustained high speeds. Short enough for good clean air-flow to my helmet so the rain-X can do its job to let rain drops get blown off my face-shield for a clear view.
Originally Posted by windmill
The biggest lesson I learned is that real world usability trumps supposedly technical superiority.