My Take
I love love love Google products, and I generally use them as much as they can, but if you are not acquainted with the "Google" world, there can be a steep learning curve. Google also likes to play with and tweak little things about their tools quite often without notice, so that can be frustrating. Students tend to also have a difficult time understanding the concept of "sharing" documents, organizing files, etc. but I find that to be an important exercise in digital literacy.
How I Use It
I have been using Google Drive since Docs was brand new in 2008. I first learned about it as a collaborative writing tool from one of my San Joaquin Valley Writing Project colleagues. Since then, I have used Google Docs/Drive in every way I can imagine. My favorite uses are as follows:
(1) Surveying kids with forms
(2) Creating "read only" handouts instead of photocopying
(3) Collaborative writing experiences for students (small and large group)
(4) "Exit tickets" where students post a question or comment on a document after a lesson
(5) Writing a "collaborative textbook" using a Google Presentation using whole-class inquiry
(6) Giving students feedback on their writing that is timely, personal, and constructive