O&O Software has been selling Windows utilities since the 1990s, and the domain record backs that up. The domain goes back to 1997, the company is named in its legal disclosure, and its privacy and terms pages are in place. Third-party oo-software.com reviews are thin, but the long archive history and moderate traffic tell the same story: this is an established software vendor.
For a software download site, the main thing to watch is whether you get the installer from the official source. This company runs its own site and publishes a clear business identity, which are good signs. The security setup is current, and no blacklist or browser warning flags show up. For anyone asking whether oo-software.com is a scam, the evidence points to no. Use normal care when buying or downloading software, but nothing here should stop you.