From https://reactos.org/faq/ https://reactos.org/faq/ "What are the differences between Windows and ReactOS? There are mainly two. Firstly ReactOS is open so

From https://reactos.org/faq/ https://reactos.org/faq/ "What are the differences between Windows and ReactOS? There are mainly two. Firstly ReactOS is open source. Secondly ReactOS is Free. Also Windows (especially the newer versions) are known to monitor all your activity by default. So if you’re concerned about your privacy or just don’t want to share any personal info, we promise (and you can check our source code) that we don’t track any of your data." That is very nice!