Best practice for managing PDF files

I’d like some guidance on the best way to manage PDF files in EndNote X6.

I use PubMed to find articles of interest. If they’re important, I want to have access to the PDF with the following conditions:

  1. The PDF should be stored with any annotations I make on it with Adobe Acrobat Pro XI (Mac or PC) or  the GoodReader app (iPad).

  2. The PDF should be available on a Mac, PC, iPad, and iPhone with an internet connection.

  3. The PDF should be available by hyperlinking from an external application such as Evernote.

I’m thinking that means storing the PDF in a cloud server such as Google Drive, and somehow associating the EndNote reference with the stored PDF file, perhaps by adding the file’s Google Drive URL to the URL field in EndNote, but I’m not sure if that’s the best way to do this. I don’t want to just attach the PDF to the EndNote reference unless it’s readily editable, available on computers that don’t have EndNote installed etc.

Thanks for any suggestions!