This suite is the same as the Ashampoo office suite, and has been regularly offered for well under $10. At that price, it's far superior to OpenOffice. And with this offer, making it free, I just can't see any reason to consider OpenOffice.
Obviously, MS Office remains the 800-lb gorilla. But if you don't need to use it, then SoftMaker is a great alternative. IMHO, it's far more usable than OO. It's much smaller, too, which makes a difference for portable installations. And it's a complete suite, unlike other apps like AbiWord.
In short: grab this while you can.