The 290x looks like a pretty awesome powerhouse. It does run SUPER hot, though, at about 95C. I would be worried about how long it will last at those high temps, but AMD seems to be okay with it. It's also pretty loud. Louder than a 780 or Titan. The non-reference versions of the card could help some with the temp and the noise but it's going to be hot no matter what without water cooling. The OC'd GTX 780 I'm running (Asus DirectCU II) averages about 65C during heavy gaming. The other reviews and benchmarks I've seen show the 290x to be more neck-and-neck with the 780/Titan, with each of them beating the other in different tests.
The price to performance ratio is definitely better on the 290 since it's $100 cheaper. But especially in "uber" or performance mode it runs really hot and loud. Just some things to consider. Obviously I'm biased, though.
The Asus 780 I'm using is probably the coolest running and quietest air cooled GTX 780 on the market and it's still definitely audible during gaming, which already bugs me a little and the heat it puts out even at less than 70C is substantial, so I just don't know about 95C and quite a bit louder.