I bought the Honda one when I bought my ride last year. A little over 7,000 miles so far, and I know it makes a big difference.
The first one I bought was faulty, and it started cracking from the inside out where the holes are cut into the shield connecting it to the brace. I rode without one for a little over a week while I waited for Honda to approve free replacement of the defective part. I ate so many bugs without it that I actually rode less as the days wore on.
I dont wear a full face helmet... heck, I dont really wear a helmet at all... but I have found that it also works perfectly when I sit in a lean-back position, and I rarely eat a bug. That said, I started wearing a bandana all of the time because my forehead gets hit like crazy. FYI - I'm 5'10".