I wasnt impressed with the statement of 2.8X performance boost over a single card set up.
Looking at the nVidia website and the links to suggested/certified power supplies, the units certified for the 3 way SLI supply between 1100-1250W.I wonder how much a good mobo + Video cards would cost. It can be anywhere from 1500-2000k on just video card+mobo if you are going to do the 3 way SLI. And I bet you need a damn good Power Supply.
I found AMD hybrid Xfire more fascinating, this has great potential the idea of running integrated Graphics with surfing, productivity etc & then switching to discrete for gaming, HD decodes sounds like a great power saving feature. Article for those interested
AnandTech: AMD Hybrid CrossFire Preview: Making Two Slow GPUs... Not So Slow