The video in the website below explains the concept. They're aren't really grips; they insert into your handlebars through the bar-end. The video tells what all they can do for you. The only downside I could see to them is, if you're running a two-stroke that is poorly balanced or just likes to vibrate a lot, you might have trouble noticing the haptic feedback. There may be other pros or cons I haven't thought of, which is why I'm throwing this out there for discussion. Let's hear some thoughts!
http://smrtgrips.com/
http://smrtgrips.com/