People moving from NV to ATI are more likely to notice any anomolies on the ATI card that weren't on the NV card. Goes the other way too.
If I didn't have an ATI card I wouldn't have seen anything wrong, if I had of moved from ATI to NV - I would have noticed the loss of the lovely, lovely ADAA quality.
As for my IQ observations. The Clear Sky issue is universal, as should the HL2 issue (I know few people have actually looked at the HL2 vids). However, the Mass Effect issue is most likely down to the IQ settings - I maxed them out. No point having a fast card without lots of AA, AF and ADAA.
I think the people who go for X2s at the mo value FPS above all else. They're either less likely to notice any issues - or just don't care. Basically most IQ issues are minor, only noticeable if you're sensitive to them. For example the Grid issue in this thread isn't a constant issue you get every frame - its the shadow cast from beams over the track. How many beams are there, would you even notice the quick flash of a dodgy shadow on the back of the car? The OP obviously did, but many won't and will outright claim its not there - because they don't see it. No body is lying here, just different view points. It would be nice to see some respect for each other. If you can't see it, good, but don't abuse people who can see it by calling them fanboys - especially when they present screenshots backing up what they see. Same as no one is abusing ATI owners 'omg you have an ATI card with obvious image quality issues - you fanboy!'.
The IQ issues I came across with the Radeons were very easy to recreate - and having 2 cards and various drivers meant I could eliminate faulty hardware or a bad set of drivers.
However, if the fan of this X2 was indeed at 100% its almost certainly faulty.