MS 2004 is $30 now. When it came out it was $69.95. Plus MS never has offered an upgrade for Flight Sim from year to year. Basically they tell you you must buy a new version if you want to use our state of the art program every 2 years.
AFP is state of the art out of the box. Heck it came out almost 2 years ago and was released before it's time. There have also been free patches and downloads for AFP direct from the manufacturer for the last 2 years as well. Over 550 free downloads. None of which you have to pay for. To get the best downloads for MSFS you have to pay for them.
So basically for $139 you get everything you'll ever need with AFP, never spend another dime.
But for thirty measly bucks it is hard to beat MS2004.
X-Plane easily beats MS 2004 and you can get it for $30 too. So in that case MS 2004 is easily beaten.