Compare apples to apples - that AB9 Pro uses the 965P chipset.
mostly anything 965 above is full Conroe Supported now. No comparing them is like comparing Genetically Modified apples to Organic ones
That's not the point - the 965 is posistioned as a "mainstream" chiposet while the 975 is a "performance" option. While the 965 is supposed to have some advantages (I believe with memory handling), it lacks some of the features of 975 boards. Yet, you compare a 965 board to a 975 board and proclaim the AB9 Pro to be better because it is cheaper.
Point is, if you're going to compare based on price, you'd better be sure that the options provide similar functionality.