I have a Penryn Macbook with the lowly Intel graphics and I don't recall ever seeing a choppy GUI and Dashboard. The 3d would be more relevant for gaming than for the 2d animations of the dock, dashboard, etc. You should be fine. The only down side is the fact you can't use both Nvidia chips at once which apparently the chipset could support but Apple decided not to enable. I'm thinking about the high end aluminum macbook. With backlit keyboard, LED display and aluminum unibody, the only things I'd be missing are the firewire and express slot. I don't think I want to write an extra $400 check for those 2 items. And Apple has already released an update of migration assistant and I bet there's now a way to do the migration via usb.