Always fancied one but never taken the plunge. Did ask a guy on an 848 on Waterloo bridge what he thought as he was wearing one. He said the first week he nearly crashed everyday as he kept looking back as it's neat!, but impression I got was it works well. Think the thing is to wear around the house to get used to it before going on the road.
I have one, bought it two years ago. The good points are that it seems well made, is very quiet to use and the mirror while being small is helpful in certain situations. The only downside is the weight and I think how much that affects you depends on what bike your on and in what position. I very recently bought a Nexx carbon helmet to replace it as I`d been looking at them for a while and the one I got was discontinued and reduced to clear so I will be selling the Reevu. I keep meaning to get it on Ebay but then forget to do it.. You are most welcome to give it a try if you like. Send me a PM if you are interested.