If you pay attention to our daily hardware roundup (and I'm sure you do), then you have probably already read Legit Reviews look at Lucid's HYDRA 200 chip, as well as the discussions they had with AMD and NVIDIA about the technology. Looking at the demo systems Lucid had on display both at IDF and behind closed doors, it is clear that HYDRA works largely as claimed, at least from a basic functionality stand point. Using MSI Big Bang motherboards, it was shown running NVIDIA and AMD cards together without need for bridge connectors. You will need to run Windows 7 to use cards from the different GPU vendors together though, as it is the only OS that allows the necessary drivers to be installed alongside each other. Being able to select the card which outputs to the display from the desktop is handily straight forward however.
When it comes to performance when compared with SLI or Crossfire, Lucid are still being very cagey, stating that they are unwilling to release numbers at this time. The furthest they were prepared to go was to say they expected "competitive performance". The reaction from AMD and NVIDIA is also somewhat predictable, defending their own technologies and generally towing the company line. They did however both say that if HYDRA delivers a substantial improvement for gamers then the industry as a whole would win (high performance and more straight forward multi-GPU gaming would likely lead to increased GPU sales). Take a look at the full article if you haven't already. Unfortunately, it looks like we will have to wait for motherboards featuring HYRDA to be released before we get some real world performance figures.