Too many mistakes here, its scary people spread stuff like this.
Some facts. Intel never said that USB 3.0 would be on Sandy Bridge. Implementing USB 3.0 will not take up lanes needed for PCI-E 16x or 8x on Sandy Bridge, since the lanes off the south bridge are now full speed (double what they were on LGA 1156 chipsets. AMD has not implemented USB 3.0 on their chipsets.
Improvements on the Sandy Bridge platform are pretty substantial, compared to the x58 and P55 nonsense. They aren't any better than x48, and P55 is worse. No SATA 6.0Gbs, no full speed PCI-E 2.0 lanes off the south bridge, no USB 3.0. At least now, they added the first two, that latter of which makes USB 3.0 implementation much easier with an add-on chip.
There's got to be something difficult about USB 3.0 implementation on the chipset, since none of them have it. If it were just Intel that didn't have it, I'd join in the whining about it. But, AMD doesn't. VIA doesn't. There's a reason no one has it yet, and considering the technical successes of the these companies, it's not because they are incompetent. We'll see it soon enough, and at least now implementing on Intel isn't such a horror.