honestly, I think most of the component nonsense in mobo advertising is nonsense. What really goes into product design that matters is never advertised, because those aspects are far too difficult to explain in a simple sentence or two in an ad.
Gigabyte has all "solid" capacitors: the technical name for these capacitors are conductive polymer aluminum electrolytic capacitors. if you've played around with electricity before, well, these still should blow up if you give them too much voltage. From the couple of datasheets I've read, it seems that conductive polymer caps aren't actually rated much longer than regular caps--about 2000 hours. I've seen regular electrolytics rated at 10,000 hours. I suspect the decision of using these caps has to do more with the fact that they have lower ESR and thus can handle more current. or just pure marketing.
Asus' claim of having better caps for the sound: if you've done anything in diy audio, you know that electrolytic caps suck in the signal path. the ones on the gigabyte board are ceramic, which should (depending on the quality they used) sound better than the big electrolytic caps. Otherwise, the value of the cap generally does not matter as long as if it's designed properly.
what really does matter for OC'ing is how well the board perform at high speeds. When working with extremely high speed circuits, all sorts of weirdness happens. the layout of the traces on the PC board and positioning of components becomes extremely important in determining how stable the board is. what happens is that the space between copper traces on the motherboards become capacitors, and the higher the capacitance between them and the higher the speeds traveling in them, the more crosstalk and signal loss you'll get.
I suspect the reason why some people can overclock more than others involves the subtle variations in manufacturing the boards and the minor differences in placement of components. Better designs should account for these differences.
Of course, saying "our pcb is designed better" isn't quite marketable.
In the end, I say ignore all the nonsense features mobo manufacturers advertise. it's better to just see for yourself which mobos oc better or perform better.