I use a Vantage Pro2. So far, I'm very impressed with just how good the spread spectrum, frequency hopping radio transmission works. The wireless part is what makes a lot of the other brands work better if you buy the wired version and then you open yourself up to lightning problems. The Davis folks seem to have that problem licked with their Vantage models.

If you're interested in keeping long term weather records, I think the computer interface will do a better job of that than the IP version.