I got the Gigabyte version and it is silent like they say and runs cool even at 850mhz core on stock volts but that is ware it ends. The fans are sharp so be careful if you are moving with any cables or just feeling for hotspots to not get cut. Also the caps and power vrm get rather toasty like most cards these days but the caps standout on this model for getting really hot. I modded mine so that the mosfets are nice and cool compared to most 460s out there. The Asus might be slightly better with overclocking but it is going to have the same problems as the other.
I would go for the Gigabyte SOC. The very quiet Windforce II cooler and high quality components really push it over the top:
"From the top of my head I can tell you that this was GeForce GTX 460 card number eighteen that we have tested to date. The overall baseline performance of the GeForce GTX 460 is of course commendable, this particular SOC card comes factory overclocked a good chunk higher, making it the fastest GTX 460 we actually tested. The card as tested today performs roughly at GTX 470 level, and that means it is in fact competing with the Radeon 6850 and sometimes even the 6870."
"It doesn't stop there though, you can really benefit from a manual overclock as well thanks to the cooler. 850 MHz is just not an issue either and thanks to the very silent WindForce 2X cooler the temperatures remain very much under control. Now if you are willing to do so, add a little extra GPU voltage as shown on our overclocking pages, if you set it at 1.088 Volts you'll pass 900 MHz. Our maximum upper limit was roughly 950 MHz, and that was really pushing it."
"At this point we have tested no less than eighteen GeForce GTX 460 class cards, and this card again is something special, it manages to impress us very much."
"With the Gigabyte GeForce GTX 460 Super Overclock edition it's all positive really, no need for a long and extensive conclusion. It is the fastest factory clocked GTX 460 1024MB model we've spotted on the market to date. If you can find it at the right price, then go for it as we would very much like to recommend it, even if it is for sheer silence and cooling performance alone." http://www.guru3d.com/article/gigabyte-geforce-gtx-460-...