According to iTunes:
Wattpad: IOS4, enhanced part navigation, add My Profile tab
eReader: fixed a book deletion problem for the on-device bookshelf. Changed the background on the iPad for the Find and Color Picker dialogs so that the controls can be seen easeir
Kobo: choose from left or fully justified text layout from reading settings. Enjoy an improved animated page turn effect. Performance and stability improvements.
no mention that eReader now has coverflow in landscape mode (At least I think it’s new.)
Nice but I wish they’d spent time making landscape mode more than a hack on the iPad instead (The controls stay in portrait orientation even if the text has rotated. Looks odd.)