I have discovered this gem of an app recently and have spent many hours now playing with my photos on an iPad. Great app, really.
While almost all editing tools generate very good looking results, I have found something strange working with Straighten Tool from the Crop section. When I use it to rotate an image, I end up with jagged edges in preview – which is understandable in a preview and generally goes away when I zoom in and let the image re-render. What is strange, is that the jagged edges end up in the JPEG version generated after I am done with editing. The jagged edges make the final JPEG images turn out looking worse than the zoomed-in preview, which makes me think there might be some issue with my configuration or the rotation algorithm. Anyone else observing those symptoms?