PWM would give you an "all in" price. Award ticket would be subject to taxes....which can range from $5.00 to several hundred $$ depending on the routing. And as previously noted, PWM would be subject to "change" fees while award ticket would be subject to redeposit fee or free depending on your status level.

In my experience, neither option is superior for every situation. As the OP is obviously doing, it is best to do the math for total cost and then determine what works for your specific situation.