Why would they compare a OC friendly board against an OC unfriendly one? Unless they're talking about a rock stable board, Intel deserves a few hands I'd say.
Anyways, If I'd compare the ST6 against the XET, I'd conclude that both are very good boards; most likely seeing a back and forth toss between the two. Yes, the XET does utilize a few very good features that the ST6 does not, but the ST6 is still a very admirable board. So if you look at it in terms of features and ease, I'm pretty sure you'll want to go Gigabyte. I've never owned a Gigabyte let alone having the good luck of using a XET, so I can never comment on personal preferences. Obviously, anyone who is giving their insight is also offering their view. If you want me to be really bias (which I try heartedly not to do), I can say that the ST6 crowns the highest fsb OC I've seen. I think it was in the mid 200's.
The only problem I see here is that b/c the XET was quite unknown and the chance that Fluid owns one with the Celly is just pure luck. I mean, I know he defends his life over the board b/c he knows all the features work. Obviously, he must have an excellent chip as well. Anyways, if only more people had known the XET before and more people had a chance of using them, I guarantee the playing surface would be much more fair in most people's mind. I love my ST6 to death and I'm so glad I was able to find one, so even if the XET works better for me, I wouldn't take the switch. Seriously, I can understand if you want to run 150+fsb, I can see why the XET is so much more easier to accomodate the "less than willing to screw around with motherboard" idea. If you do modest OC's to 140fsb and below, I really can't see why you want to pay the "extra" price for features you won't use. I'm strictly talking about the mild OCers by the way.