I have all three - OfficeSuite Pro, Quick Office Pro, and Docs To Go. All of them seem to work fine (although I agree with dmmarck, that occasionally a document won't open correctly - formatting issues, usually - in one and will be OK in another). I bought Docs To Go years ago for my BlackBerry because it was the only thing I could edit or create docs with. This isn't so much of a problem anymore. The other 2, I picked up for free at various times.