Davis is the best system out there and one of the most trusted in the weather community. I had years ago the Lacrosse and Oregon Scientific and those systems broke within a few months of heavy weather. Davis provides you with the fastest updating sensor readings as well as the most flexibility with your data. Its expensive but worth the initial investment. Mine has been running for nearly 4 years on a salt water river and hasn't hiccuped yet. Even the batteries are still holding. I only had to replace the batteries on the fan aspirated shield once. Search around and you can find some good deals. Typical refresh times on the wind speeds are 2 seconds.
I'm going this time with Davis. Which one would you choose? The Vantage Pro2 or Vantage vue.
Tough call. I personally have the Vantage Pro2 Plus but that can be pricy. The Vantage Vue is the economy version of the Vantage Pro2. Basically all the same features but the build quality is a little lower. If you can afford it go with the Vantage Pro2 but you can't go wrong either way.