I brought the 1-Wire UV Sensor about a year ago from Hobby Boards, however there were issues with it working on the 1-Wire bus. After a little too and frowing with the supplier, the problem was rectified, their support was very good. So the sensor has only been connected for the last few months, not much Sun this time of year (March 2012), so it's only picking up very very low levels so far!
The only issue with this sensor is the fitting it to a waterproof housing. The housing supplied is not waterproof. The issue in rehousing this, is the window that the sensor needs to detect the UV, has to be of a special material, not easy to source in small amounts, so I had to use the supplied housing lid with the supplied 'window', but integrate it into my own waterproof housing. I did consider removing the 'Window' from the supplied case, but this looked like I would do more damage to the perspex that worth, so I cut an extract hole the size of the perspex window in the lid of the water proof case and epoxied the hole top part of the Hobby Boards case in, worked!
You will notice two lumps of metal in the box, these are lead, to stop it blowing off my flat roof.
The next image shows the sensor placed in a clear area of the flat roof, which gets the Sun nearly all day, so the readings should be quite accurate over the whole day being that the Sun is out, but then we do articlesin the UK :-)