With tiny knobbed centreline tread and small shoulder blocks, the System 2 certainly rolls fast - especially at high pressures - making it an awesome tyre on tarmac hardpack sections. The centreline also adds some steering stability in sloppy or sandy conditions and it turns in easily.
However, the centreline slips and slides badly on any raised obstacles, such as damp roots or rocks, while the small, rounded knobs have very little bite on loose ground. They give a predictably early slide rather than a sudden snap out, though, and the tread clears muck pretty quickly. It's also reasonably tough and long lasting for a race tyre, although the high weight for its size can dull acceleration/agility.