Wilf,

P-3's are extensively employed in both Iraq and Afghanistan and are valuable platforms for a variety of functions. The problem is that there are simply not enough ISR platforms to meet demand, P-3's included. I have a friend who is a P-3 pilot and their optempo is quite high.

UAV's have advantages because they can be fielded faster and provide more ISR for a given amount of resources - they have longer loiter times and one can get more flight-hours per aircrew than what you'd get with a manned aircraft. It's also easier to covertly monitor a target with a UAV than a large-multi-engined aircraft. For Afghanistan in particular, lack of ramp space and logistics favor UAV's, especially those operated from distributed locations.