I'm late to the topic buuut..
Blender on a CD 1.8 2GB Rev.A Macbook with Leopard is pretty terrible - i boot into windows to run it. Maybe on the newer GMA chips it's better.
It's only been like this since the Leopard upgrade, it was fine before that, but there's a huge amount of UI lag now, things take a while to actually happen when you click, which makes it pretty unusable. 🙁 Hopefully they'll fix it soon. It's not just me, lots of users have mentioned it online.
On Tiger it ran like a trooper, so a newer Macbook would be very capable. 🙂