Legit Reviews decided not to visit the AMD event because they were NVIDIA's guests in Montreal, but they did receive a bunch of pictures and benchmarks from AMD, which you can check out over here. There's still no final conclusion regarding the performance of AMD's new flagship, it seems the card will beat the GeForce GTX 780 without a problem but Titan will be a harder nut to crack.
In Bioshock: Infinite with the Ultra preset the AMD Radeon R9 290X ran at an average of 44.22 FPS and the NVIDIA GeForce GTX 780 was at 39.63.This shows a significant 11.6% performance advantage for the new AMD Radeon R9 290X with the Hawaii GPU.
Tomb Raider showed the AMD Radeon R9 290X averaging 43.0 FPS and the NVIDIA GeForce GTX 780 was at 40.8 FPS. This would make the AMD Radeon R9 290X roughly 5.4% faster than the NVIDIA GeForce GTX 780 in Tomb Raider.
These legit benchmark numbers should help shed light on a number of things. For one the AMD Radeon R9 290X appears to perform better than an NVIDIA GeForce GTX 780 at 4K resolutions, but pretty much everyone assumed or hoped that would be the case. It should be noted that these results are also on beta drivers and as time goes on we expect AMD to get some more performance from the brand new 28nm Hawaii GPU.