We have covered out use of SnapSeed a few times here. It is a Universal photo editing app that runs very nicely on the iPad. What makes it an app we keep mentioning is the unique editing actions that are all finger swipe based. Rather than have a filter that you apply and possibly a slider to tune the effect, SnapSeed has you move your finger up/down on the screen to choose the tool you want to use and then left/right to adjust the percent of application. A very natural action that allows you to keep you eye on the photo your adjusting.
While SnapSeed covers a nice selection of effect groups, the particular group we lean towards is the ability to pinpoint where you applying an enhancement. You do not have to decide how light or dark adjustments to the full photo you will have to live with. Instead SnapSeed lets you adjust small areas. The variable size and shape tilt shift shown below is handy too!
Not sure about how long the ‘FREE’ pricing will last. The developers of SnapSeed just lowered their price this morning without comment so it might be a ‘today only’ offering.