Really? The DVI spec says you shouldn't have a cable more than 5 metres, and I'm running the cable I posted on a 5 metre run with absolutely no issues, the picture is perfect! Yes it's shielded, in fact I have yet to see an unshielded cable no matter how cheap they are. I paid £4.88 for mine.
Now, the more expensive cable may be stronger, and look nicer, but so say that it will give a better picture is complete rubbish. If the cable (no matter how cheap) did not work then they would not be allowed to sell them, which includes any resistance, inductance or capacitance that is actually high enough to cause problems... Simple as that.
I'm not sure if it's dual link - I use a 19" monitor at 1280 x 1024. It's definitely not DVI-A tho, as they have 4 pins around the long flat pin.