For 99% of users, VersaWorks 6 is the correct choice. It has a modern UI, better color management, and native 64-bit support.
Finding a direct download link for Roland VersaWorks 4 can be tricky because it is a legacy version (released around 2010). Roland now primarily supports newer versions like VersaWorks 6 Download Center - Roland DG
If your hardware supports it, it is highly recommended to upgrade to the latest version via the Roland DG Download Center: How to Download & Install Versaworks 6