I took Dan's advice and ran my own test.
Here are images taken using the Quick (top) and Enhanced (bottom) modes. They look similar from this view. (Artwork by The Secret Hermit Micki Wilde)
I loaded the photos into my PhotoSize app and there is indeed a difference.
When blown up 503% however you can see that there really is an improvement on the resolution.
Quick Mode image blown up (below)
The enhanced version blown up shows less pixelation.
ClearCam is available in the App Store for $0.99