Upgraded to Yosemite this morning.
I am astounded at how gorgeous this operating system is. Everything looks sharper and crisper, with more vibrant colours. I have all of my WeatherCat tools, gauges, graphs, etc. on a secondary monitor, an old Dell HDTV monitor I picked up several years ago for US$130. Even the Cat on that old monitor looks a little better! I know that looks are only on the surface and I haven't delved into it the innards yet, but I like what I see.
WeatherCat is purring along nicely.
Computer: Late 2013 27" iMac 3.5 GHz i7, 24 GB RAM
OS: Mac OS X 10.10 Yosemite
Hardware: Davis wireless Vantage Pro2 Plus, WeatherLinkIP data logger
WeatherCat version: 2.0.0 (build 4475)