This post has been corrected from the original: Google Spreadsheets is in beta; the previous version of this post said it was not. The text and headline have been changed.
I've been using Google Spreadsheets for the past week to coordinate coverage plans among several writers here at CNET Networks, and I'm sorry to report it has not been a happy experience. Several times the spreadsheet failed to load (giving me only the first few rows), other times I received "connectivity lost" errors, and I also lost small amounts of work. We've been told Google Spreadsheets constantly saves work on its servers, but in my experience it does not do so reliably.
This is what can happen when you trust your work to beta products. Don't do it, folks.
I really want this product to work, by the way. Google Spreadsheets' collaboration tools (real-time group editing with an attached chat window) are absolutely freaking incredible. You don't know what it's like to work with a remote coworker until you've tried this.