The Titan is ~£800 and the 290X is (apparently) £550. Why are you guys balking at the price if the performance is supposed to be slightly better?
We haven't seen enough in the way of benchmarks to say it's a Titan killer. Meanwhile, a 780 will also get pretty close to the Titan, and reference 780s are going for £50-75 less than that 290X price.
Both cards are a good £50 dearer than I was hoping for.