What I'm using:
#TwentyTwelve WordPress theme
What I'm seeing:
When selecting the icon theme from store settings > presentation, I'm noticing a slight difference in the CSS when hovering over the buy now / add to cart button. When hovering over the button, it changes from a beautiful, subtle button to a rounded button with bold text.
This is just one of those things that bugs me, so I'm going to look into it in effort to remedy the problem.
When using twenty twelve, opting to select "none" in the store settings > presentation area fixes this, but you don't get the cool little icons or horizontal alignment for your buy now button and product meta information (price, category, quantity).