At $149.99 (plus $5 for shipping), it's a smokin' deal, especially considering that a single license retails for $119.99.
The deal just got better: Amazon has the Windows 7 Family Pack for $132.99 shipped. That's slightly more than $44 per license, a very reasonable price for upgrading your XP- or Vista-powered PCs to Windows 7.
Speaking of that, Vista users can just pop in the disc for an in-place upgrade, but XP systems require extra measures: there's no direct upgrade path from XP to 7.
Fortunately, there are ways around that. A utility like Laplink PC Mover Upgrade Assistant, for instance, makes in-place upgrades from XP to 7 fairly painless. It normally sells for $29.99, but Amazon has it for $19.99--might as well toss it in your cart while you're there.