There is some video editing software that you can buy that supports amd's open cl. So a apu would work ok.
Basically all of the laptop cpus are run at slower speeds to save power. The intel quad core cpus are faster but unless it's paired with a nvidia or amd gpu, intel's integrated graphics is slower and not as well supported.
http://developer.amd.com/community/application-showcase/
It does seem like your stuck with software that amd is partnered with if you go with a apu. But the choices seem pretty good.
There is of course Nvidia's cuda.
http://www.nvidia.com/object/gpu-applications.html
The apps for nvidia's cuda tend to be for the Tesla or quadro workstation cards and the geforce gpus are slower.
You will have to do some research and pick the right apu or cpu+gpu to be able to do video editing on a laptop but it can be done.