Photoshop Touch is a full-service photo editing app. It's available on the iPhone, iPad, and legions of Android smartphones and tablets, and is really most appropriate when you need to do heavy lifting on one of those devices – though it's no competitor for the real thing. It's perhaps more appropriate for roughing out ideas, comps and adjustments when you're out and about or kicking back in front of the TV.
There are differences between the tablet version (£6.99/US$10) and the smartphone version (£2.99/$5), but they boil down mostly to screen real estate.
All mobile controls are present on the phone version, but you may have to poke around to find them. The interface and performance on my iPhone 5 and my Samsung Galaxy Nexus were identical—and impressive. In fact, apart from opening or saving large files, there is very little wait or lag time on any of the devices I worked on, including second- and third-generation iPads. I didn't experience a single crash.
This review goes back to the 'kick back in front of the TV,' sort of Adobe Photoshop. It almost feels as if this photo-editing has the mix of complex and yet easy adjustments that you could do with your eyes closed. What I thought was a highlight, was the fact that even with a second and third generation iPad, the system did not crash. That to me has rewarding results, in itself.