blueemu the difference is that white hasn't commited to d4 yet & his development advantage shouldn't be underestimated.
Jerry_Attrich is an expert in my area who specializes in this line: he's currently 2125 blitz (99.5th percentile) & has countless wins with his pet opening on here.
mike's in my friends list if you want to see the opening in action... just click on any game he's won.
Challenge me