AMD's new HD 5830 leaves me with mixed feelings. In order to achieve their product positioning and pricing strategy, AMD has disabled key parts on the GPU chip leaving it severely crippled in my opinion. It is a bit sad to see such a potent GPU sit below HD 4890 performance levels. Personally I would have expected AMD to deliver at least HD 4890 performance, but this is clearly not the case with around 10% difference between both parts. Given the performance I think a $229 price point is a bit steep, but over time this will change. Once the card goes below the $200 mark it will become interesting to a bigger market. I also found it hard to declare a clear sweet spot resolution for this card, it feels a bit too slow for 1920x1200 (HD 5850 territory), but also offers more than enough performance for the 1680x1050 (HD 5770) resolution. If DirectX 11 and EyeFinity support are not of key importance for you, you may be better off with a (used) HD 4890 for the next months to come. If you can manage to spend $299, the HD 5850 seems to be the better choice.
ASUS has delivered a very solid implementation with their EAH5830 DirectCu. The new cooling solution can deliver good thermal performance and very reasonable fan noise topped off by good looks. Power consumption of all HD 5830 cards is higher than other HD 5000 Series cards, but it still better than most previous generation cards or offerings from NVIDIA. Overall the HD 5830 is a solid card, but definitely not the game-changer that the HD 4830 was.
Finally it should be said that the HD 5830 will help AMD from a business perspective. It gives them the option to harvest manufactured chips with small defects which will help offload the production cost for the higher-end products using the Cypress GPU.