We have both of the Cuisinart and Kitchenaid 14 qt food processors. I find making/kneading the dough creates a lot of heat in the food processors. Using the pulse function when making pie crust much less so.
For bread doughs/pizza crusts, we use a Kitchenaid 6 qt mixer. The mixer handles the kneading of the dough better than either of our food processors. Technically, our mixer has a 575w motor. With differences in the blade/attachment speeds, I would have to assume the gear reduction in the mixer is very efficient when compared to the food processors.
We're fortunate to have both options available to us. When comparing actual usage, our mixer is used 5:1 over the food processors. When the option is one appliance, a lot depends on whether you are going to be using the food processor primarily for doughs or also to chop/dice/grate/etc.