Summary: I used this to replace a lower wattage 3 year old Seasonic power supply. Installation was pretty straightfoward, except for the fact that it did not like the cables that came with the Seasonic. The plugs were just different enough that they would not work. That was rather irritating. Not sure if that's Seasonics fault or Corsairs though. But it puts out tons of power and is quiet enough, even under load.
Summary: This psu worked for an hour or 2 and then failed and fried my motherboard... Socket 1366 i havent even been able to find a board yet to test to see if it destroyed anything else. Might want to look elsewhere for a psu. My mind is blown as well cant believe this from Corsair :( UPDATE 5/20/2013: Finally replaced motherboard.... PSU fried both video cards as well.... motherboard = 250$ OS = 150$ ATI 6870 x2 = 500$ TOTAL = 900$ OUCH!!!!
Summary: Had this for 6 months running an i7 3770k overclocked to 4.5Ghz and running 2 GTX 660s in SLI. It's still pumping juice into my rig very well and doesn't waste power by having the fan on un-necessarily. Great PSU!
Pros: - Fully modular, - Clean cable sleeves, - You can buy individual sleeved cables in different colors off the Corsair website!, - Fan only goes on when needed
Cons: - A little bit on the pricey side, but for what you get, it's worth it!
Summary: Awesome PSU. Very easy to install and easy to keep things looking neat and tidy. Plenty of power for everything and then some, it's definitely the best 850w power supply in my experience. It's quiet and runs perfectly well, would definitely recommend.