Although we don't have a reference card to cover for the launch here are most of the reviews from our affiliates.
AMD Radeon HD 7970: 28nm Tahiti GPU Reviewed @ HotHardware
AMD Radeon HD 7970 3GB 'Tahiti' Review @ Vortez
AMD Radeon HD 7970 Launch Review @ Neoseeker
AMD Radeon HD 7970 3GB Video Card Review @ Legit Reviews
AMD Radeon HD 7970 Video Card Review @ Hardware Secrets
AMD Radeon HD 7970 @ techPowerUp