Pros: Quiet, Great cooling capacity
Cons: Heavy, Large size might not fit all cases.
I bought my 6990 to replace my 5970 + 5870 tri-fire setup, as I wanted only a single card solution. When I first turned it on and started gaming, it sounded like a Hair Dryer!. It was even louder than the 5970 fan!
I was thinking about water cooling and bought a Koolance Exos 2 external water cooling kit only to RMA it since the pump was dead when I received it. While I was waiting for the return, I saw this cooler and decided to take the plunge.
Installation is relatively simple and the instructions are easy to follow. The temps on my card fell from 45 degrees to 35 degrees at idle and from 75 to 61 at maximum during gaming. The noise drop was HUGE. Even at 90% fan, you can hardly hear it inside the case.
The only drawbacks of this cooler are the weight and size. The weight of the cooler when installed onto the card is quite substantial. When installed it does cause the card to bend quite a bit on the horizontal. To combat this, I have cable tied the end to the HDD support on the side of the case, but you will have to take this into account when installing.
The size of the cooler is also an issue. The cooler just fits into my DF-85 case. It extends the length of the card by at least another 3-5 cm. With the 6990 being over 30cm, make sure you have a BIG case to fit it all in!.
Some would say the price is steep, but for an air cooler that does the job well and will give you no leaks or maintenance issues, I think it's a bargain! (and I saved almost $270 in costs from water cooling).
I can definitely recommend this cooler if you are looking for an air cooling solution for your 6990.