The math shows that p2pool will come out better over time (plus lower fees, in theory lower orphans, mining right to your own address so no worries about lost/stolen coins), many people are impatient or haven't read enough and won't give p2pool a few months to show its benefits. 

The OP is discussing doing a longer-term test to show this.  Pools have plenty of variance so even if the math shows that p2pool is going to come out ahead, there are weeks where it won't.  And visa versa, weeks where it would come out way ahead.