I just found this thread and its great! We're looking to role out Chef for our entire infrustructure (moslty Linux, but around 1300 windows). I'm the Windows engineer working on our build using chef. For the most part its been great, just learning Ruby and how Chef works. The most difficult challenge I've run into and something I wish Chef would make easier is dealing with our proxy. Chef tries to go to the internet for everything, most corporate IT have proxies that get in the way. So when I try and install chef-vault it fails saying it can't reach the internet. I also wish there was more examples geared toward the Windows environment.
cookbooks I'm using
powershell (installs powershell)