Love using Docs as a source. A while back I wrote a service[1] which creates an API using Google Drive and Docs as a source. Docs are naturally pages, and the Drive folder structure builds the hierarchy/tree of pages using a pretty simple naming convention (Mainly for ordering). The CMS/collaborative aspect is great. Some things that aren't ideal are:

  - Seeing print-style page breaks in docs
  - Formatting images. Although, having Google host them is nice
  - The html Google Drive generates is inlined, inconsistent, and pretty nasty. I resorted to using markdown in Docs.

1. https://github.com/psaia/allwrite-docs