If it was me I would be looking at the EVGA Supernova G2 850w. It's a Superflower built unit and is based on their Leadex Gold platform and has a whopping 10 year warranty. Jonnyguru gave it 9.9 out of 10 in his review.
Alternatively, there is Superflowers 850w Leadex Gold but those leds where you plug the cables in would do my head in. The whole 5 year warranty is with OCUK though.
Get the EVGA. If it breaks anytime in the next 10 years you get a replacement. It's cheaper too!!
+1 for the evga g2 850w
The EVGA is a Superflower PSU I believe and the AX860i Flextronics.
Both are very reputable. I'd be tempted by both tbh. Though the EVGA as mentioned gives 10 yr warranty vs 7yr Corsair, but the Corsair gives Platinum efficiency vs Gold. Read some reviews and take your pick, I think it really is a personal opinion and there's no wrong or right choice between the two.
For what it's worth, I went for the evga g2 850w after reading jony guru's review.