These are very distinct fragrances. I would never think to directly compare them, apart from describing them against each other since there's such a contrast. Chanel Sycomore is a smoke-touched rich vetiver, with a hint of sandalwood in the base. It's mysterious autumn. Terre d'Hermes is citrus, cedar, and flint, with a bit of vetiver. It's a summer day stretching from mimosas to a warm evening rain. Entirely different experiences, both.
If you like both, both are worth owning. However, Sycomore gets the edge as being one of the very best fragrances for men (or adopted by men) out there. A must, in my opinion.