TBH I don't know. When Ultra originally released the 800W and 1000W X3 units based on the Andyson AD-800 platform they were pretty good at the time, but the 12V rail was a bit weak compared to others. I'm really not sure why they came out with the 850W version, especially since it has the same specs as the 800W. Odds are it is the same design as the 800W X3, but knowing Ultra it's hard to say if the 850W is built to the same specs as the 800W. Just them releasing a new model to replace the 800W is suspicious enough, especially since none of them have made their way into a respectable reviewer's hands. And most modern 800-850W PSUs come with 65-70A on the 12V rail. The 800W and this 850W only come with 55A. You might as well pick up something like the
Antec TP-750 Blue. It's made by Seasonic on a much newer and better performing design with 60A on the 12V and it is cheaper AR.
As for why people recommend Corsair, it's because it's the easy choice. They don't sell any bad PSUs, so it's easy to say Corsair instead of specifying which models are worth buying. They also tend to compete well at price/performance and their hx750 and hx850 are some of the best PSUs on the market. But for example, the tx750 and tx850 are based on the CWT PSH platform. It isn't anything special, but it's a solid design so long as you keep ripple in check at the higher wattages (like Corsair has). There are better options, like the Antec TP-750, but it's still a reasonable choice if the price is right. Also they have good CS.
