There is a bug :Is it safe to activate iCloud Drive now?
I am running iPhone 6 w/ iOS 8.0.2, Ipad 3 Retina also on 8.0.2 and late 2011 Macbook Air w/ Yosemite Beta 4.
I've been using it for several weeks and it's not bad. I'm just having some issues with video files synchronizing to the iPad.Thanks. Glad I asked.