Yes you read it correct that Windows 8.1 is free for you to download and use, provided you have already paid for Windows 8. Although Windows 8.1 is Free for existing users of Windows 8, still downloading and installing another operating system does requires careful planning so that your data remains intact and you do not loose anything in transition from Windows 8 to Windows 8.1. This new version of Microsoft Operating System is going to attract more customers to upgrade from Windows Vista or Windows 7 to Windows 8.1.
Although new features of Windows 8.1 are still to be uncovered, but there are good chances that the new features of Windows 8.1 could have been released as Service Pack or something like that. Re-Installing an Operating System is not an easy task taking into consideration currently installed Desktop and Windows 8 Style Applications, Data, etc.
In case you are an existing Windows 8 user willing to download and install Windows 8.1, do take care of your existing applications and data on your Windows 8 computer. The good news for people willing to buy Windows 8.1 is that they do not need to wait for Windows 8.1 to get released and they can buy Windows 8 now and upgrade to Windows 8.1 totally for Free.