Aleksa, your statements apply well to the one review I've read so far, but that review is based on a pre-production design and older drivers.
I think at least some production cards will be more energy efficient by design and the performance will increase by some extent as new drivers are released.

Still, the 5830 doesn't seem to be as good as I hoped for.

The 5830 aka ATI Fermi is the real picture of the ATI 5830 compering to ATI Evergreen lineup of video cards.

The 5830, is on pair with 5850 just in terms of power usage - heat on load, same PCB, connectivity and cooling.

5830 is 3% - 8% faster than 5770, the best deal at the moment its 5770 and 4890.

5830 is overpriced, hot, buggy and slow it terms of price - performance compared to ATI 5770, 4890 and Nvidia 260.

If you need DirectX 9,10 and 10.1 best choice is 4890. For the fans of DirectX 11 best choice is 5770 or 5850.

The 5830 is not filling the gap between 5770 and 4890 with current pricing, power, heat, performance and drivers, in turn it creates a Grand Canyon. :-D