Installed my Rainwise MKIII Saturday, replacing my four year old Davis VP2+. The battery changes on the VP2+ were getting closer and closer. With the steep pitch of my roof it's difficult to get up there (except for my son, but he's leaving for Navy Seals in September). This last week it just quit... "supercap" popped and was leaking. Thought about going wired but decided to try something else for not only technical but professional reasons.
So far I'm very impressed with the Rainwise. It has a sealed gel cell battery in the sensor unit that probably won't need to be replaced for about five years (from past experience with these batteries). The term "tank" that was used earlier describes it well. Housing has good sealing. The way everything inside is assembled and protected is very good. It doesn't have solar and UV sensors but I can live without them and not have to scale the roof every four or five months. Computer interface is only RS-232, but I have an adapter to solve that. I had to make a slight modification to slide it on top of a mast but it is very secure without having to balance it while tightening U-bolts (the included mount works on a tripod support out of the box). It is top heavy (about seven pounds) so if you do mast mount be prepared to add guy wires. The solar panel is a little flimsy but the only time you have to watch out for it is during installation... otherwise it appears it is going to do the task as needed.
Overall the Rainwise cost more than the Davis (especially a wired one) but, overall, it looks like it is going to be worth it.
