I turned on iCloud drive on my iPad Air and iPhone 6 yesterday as I wanted to give it a try and I was fine with the limitations until Yosemite gets released. I noticed one that that is driving me insane: you can't change the description of your iCloud e-mail. I know it's not a big deal. I have all my e-mail descriptions set to to be actual e-mail address and I have had this setup since my 3GS.
Sorry, I just had to rant.
Sorry, I just had to rant.