I have used Google Docs before. I recently helped a friend edit her resume on Google. Instead of sending an attachment to multiple parties, she used Google to invite several friends to proofread and edit her resume online.
I did find Zoho Writer pretty intuitive to use. The features are comparable or better than Google Docs. However, since I already have a Google Account, I'd rather continue using this vs. creating another account with Zoho Writer.
I don't really use these tools for work but rather for personal reasons.