If it offers manual controls thats kinda a big one, I haven't looked that much into iPhone photography beyond Instagram (apps other then the built in camera) but this could be interesting. I think offering some control over exposure is a big leap already in quality of images. I don't know if there are any other apps I have seen which offer control over shutter speed or exposure but I could be wrong...or misunderstanding this. Lets download it and see!
Updated: I just downloaded it, and it seems you can't manually control the shutter speed, I don't know if I'm missing something, but thats disappointing.