GoG previously had the original PC port of Substance available, but was unlisted for reasons I'm not entirely sure of. The current port for modern systems, the Master Collection, is a minimum effort port of the HD Collection version from 2011 which was based on the Xbox port of Substance. The Xbox port suffered from a laundry list of issues in comparison to the original PS2 release that the HD Collection only added to, and the Master Collection added a deluge of new issues on top of those. The original PC port was also based on the Xbox port and similarly suffered from a host of problems that fans had made efforts to fix.
Honestly, the results were mixed, but even without those fixes it's at least one less layer of porting problems.