Gamespot have rather quickly flung together their review of Quake 4, scoring it a decent 8.0/10.0. Here's their overall, final verdict:
"The Good Sharp single-player campaign; Some of the best graphics around; Weapon upgrades make you rethink how you use your arsenal along the way; The Bad Multiplayer sticks too close to Quake III's blueprint; Kind of a resource hog; Vehicle sequences are a little too basic;"
Plus, over at AMDZone have thrown up their first benchmarks of Quake 4 FPS rate performance results on their AMD Athlon 64 3800+ X2 2.0 GHz, 256MB G-DDR 3 ATi Radeon X850 PT EE and 256MB G-DDR 3 nVidia GeForce 7800GTX, GeForce 7800GT SLI, and GeForce 6800GT graphics cards, plus with 512MB of cosair PC3200 dual-channel 6.4GB/s of memory bandwith pumping DDR400 SDRAM system setup, check the page(s) out.