I have been using it for 12 days now about 250km per day (5 or 6 hours) to listen to my GPS/Phone. It works very well.
The speakers are thick but fit my helmet perfectly because my helmet has a removable plug in the ear area just for the speakers.
At high speed and high wind noise it was a touch difficult to understand the spoken words AND then I found some adjustments on my PHONE, after making those adjustments I hear it just FINE.
I did a test for Derek, rode for about 6 hours WITH my custom, made in my ears, earplugs in place at all times. Certainly cut down the wind noise. Also reduced perceived volume level of the GPS spoken directions but intelligibility was as good or better. I was riding F700GS so not a lot of wind protection. Very short windscreen.
When going max speed of about 65, again, heard GPS voice talking just fine with total recognition of what she had to say.
Battery life is about 7 hours IF you listen to music constantly. The way I used it for GPS directions, will last longer. REcharge is from standard mini usb phone charger and took a Maximum of 1 hour.
Remember, you cannot use it to talk with others on the ride, but for hearing your GPS or Cellphone, Its GREAT.