Final answer:
Keynesian economists may criticize the size of the stimulus, while neoclassical economists may critique the focus on demand-side policies.
Step-by-step explanation:
Keynesian economists may criticize the American Recovery and Reinvestment Act because they believe the size of the stimulus was not adequate to fully stimulate the economy. Neoclassical economists, on the other hand, would be critical of the focus on demand-side policies, as they argue that the economy will naturally correct itself over time without the need for government intervention.