I had one of the ebay cheapies on the roof for around 10 years. The plastic and bearings eventually failed on the anemometer cups but it was otherwise robust. There was a memory leak issue with the supplied software it would gradually grind your PC to a halt, some of us used a third party application which could access the data and display as a webpage for remote access, Weather Display
http://www.weather-display.com/index.php Weather Display is a little tricky to get running but it works as advertised.
Quality on the cheap weather stations is a bit hit and miss but generally they work well for the money. Lots of info in this thread.
http://www.iceinspace.com.au/forum/s...ad.php?t=29959