Yes, the aperture blades are rounded. The EMD supposedly allows more precise control over the aperture setting.

Initially, I felt this lens was rather blah. But having this lens on a gripped body or 1D X will basically be like having no lens at all - it will barely stick out beyond the bulge of the pentaprism and portrait grip. That means the camera body - with a lens for taking pictures - can fit in a small case like my Lowepro Utility Bag 100 AW, and I can take that in my computer satchel on overnight trips, etc.

So, if the IQ is decent (will wait for ISO 12233 comparisons on that front), for a mere $200 it's interesting. Sure, f/2 would be nicer, but coupled with the ISO capabilities of the 1D X / 5DIII, f/2.8 should do fine.