Being able to use DDR2 ram for 4x4 and DDR EEC for other 2+ systems is plus over FB-DIMMS and they have better chip sets with SLI and more pci-e lanes then Intel systems.
Being able to use DDR2 or Registered DDR2 over FB-DIMMs is a pretty obvious advantage, agreed. Personally, I think AMD's biggest advantage is their point-to-point system architecture (i.e. HT), which always shines in 4-socket systems or even 2-way systems in some cases.
What I meant with Tigerton is that Intel already showed off a Tigerton-based 4-way Clovertown system
9 months ago working at 2.66Ghz, and Tigerton
should launch in september @ 2.93Ghz. This is a tough platform to beat, and even with AMD's platform-level superiority, we'll still have to see if the initial 2Ghz Barcelona is enough to stand its ground against Tigerton... If they can pull 3Ghz off, then Intel would have a much harder time.
Anyway, AMD's new tech will debut, like Hammer, as Opterons first, so that's why it's interesting to keep Tigerton and Clarks. Right now, it's all speculation...