Well, it's by a big name, so it's got to be the best, right?
Personally, I would have gone for Camera+ - not free, but at 59p, it's hardly going to break the bank.
This allows users to take photos, edit them and them share them. I won’t go through the list of the camera functionality, but features like exposure control, stabilizer and a grid for lining up shots is very handy… plus a self-timer, which Adobe is charging extra for. I haven’t used this latest version of PS Express, but with the last one, Camera+ won hands down in terms of taking pictures.
In terms of editing, Camera+ allows you to crop, rotate, straighten, plus apply a very decent number of effects and filters (much more than here). Normally, the end result is good and there’s no need to fiddle around with contrast, saturation etc. However, if I’ve found that there was a need to, then the best tool is Mill Colour – free and seriously good stuff… now things might have changed in this version of PS Express, but the previous one as a tool was substantially inferior to MC.
Although not free (but very cheap), Photogene and Photoforge have always been considered to offer rather more functionality as a photo editor than PS Express and it might be interesting to compare these apps sometime.