In the latest version of SlideMagic, all boxes now have slightly rounded edges. You actually need to look carefully to see it, but the impact on the overall slide layout is dramatic, things look more friendly.
Apple is a big believer in round edges in its designs. It claims that sharp edges do not appear in nature and are not natural shapes. (Well there are crystals). But I think Apple is overdoing it. The camera unit on the back of an iPhone for example has too large of a corner radius, and in many of the app screen designs the corner radius of the window, hardware, and icons clash.
In PowerPoint and Keynote the default setting for a corner radius is also too big, and there is no way to adjust them precisely to the same value (you can only drag with a mouse).
The edges in the SlideMagic PowerPoint conversions stay sharp for the moment, I can programmatically tweak regular shapes in PowerPoint (so no more mouse dragging), however for images I still have an issue.
The latest version of SlideMagic is 2.4.45 and you can download it here for free (Windows and Mac).