Helicopter Ops in Iraq

The news of downed helicopters in Iraq seems to be very common. Just today an Apache was lost to enemy fire.

* The losses in afghanistan seem to be lower (Only my uninformed impression). How is the flying/combat there different?

* Is the current attrition in Iraq high or is it ‘acceptable’?

* What are the typical reasons for Blackhawk losses? (MANPADS or small arms?)

* Is there any inherent flaw in the Blackhawk design?

* Is the Blackhawk really bad or is the resistance too good?