The pictures you guys are posting doesn't show the quality. You are all uploading the resized "low resolution" version. I don't know if your taking 3MB shots or if the place you are uploading your pictures to are resizing them, but either way it makes it pointless for quality comparison.
To see the true quality of each picture, I want to see the full 5MB version of the image taken. Only when you see the full sized version can you see the detail (and grain) taken from the shot.
They all look outstanding when you "shrink" them.
Judging from the pictures provided so far, I honestly can't tell a difference in quality between the app examples and the stock camera.
I also use Picsay for my editing needs, so effects is not a priority for me. Like t he guy above me posted, its the quality of the captured pictures that we need improved. You can always put them on a PC and use other editing software like Photoshop if you want hardcore effects.