Any Experience With the Seasonic XP-860

I am in the process of getting a new system, so far looking at 3770k with a GTX 680 or 670, not sure if I'll do SLi or not, probably won't though, so I don't need this power supply, but I want to know how the fan settings work for it. I saw that it won't turn off until it's under load, but what is the trigger for it and how loud is the fan when it kicks in, as in will it be louder than let's say my current power supply or my reference style cooler on my 6970? Also, I don't know much about the efficiency ratings, is Platinum really worth it/what does it do to help me? I just assumed it would save a bit on my power bill as I never turn off my pc. I may also do custom watercooling in the future, as of this point I'm looking at an NH-D14 though, so I don't have to maintain it.

No experience, can't find any reviews as its brand new.
I would be shocked if it was anything less than excellent.
It's likely to be very quiet at low load (possibly not even running the fan) and quiet at medium load. At full load (you won't get anywhere near it with a 680, with two 680s you'll still be at or around medium load) it may make some noise.

If you have to pay more than maybe 10% more for platinum over silver it's probably not worth it from a power savings standpoint.
The more efficient the unit is the less cooling it needs though, so in theory the quieter it will be at a given load.
Do note that the above is not always true in reality.