I bought one of these cards about 2 weeks ago from OcUK.
Mine has no overheating issues, that was with the version 1 cards I think. It was something to do with ASUS not cranking the heatsink down tight enough as they used screws that were slightly too long. These are now version 2 cards and all fixed
I can confirm that mine is voltage unlocked as well. I run a 24/7 overclock of 1150/1550 @ 1.180v can do 1200 @ 1.210v and have benched at 1265 @ 1.3v. Memory will go to 1700 but set it back to 1550 as it doesn't make much difference.
As for the temps, 2/3hrs of Crysis 3 in a warm room using a HAF XM case, I get, max core 63-65c, VRM's stay below 66c and does this without the fan going over 40/45% (custom fan profile) and is very quiet.
IMO it really looks and feels a sturdy, quality product when you get it out the box. Even with it being big it holds it's weight well and does not sag at all.
All in all I am very happy with the card and in my opinion I can only recommend it