There are hundreds of camera apps on the App Store. I always feel that using the default camera app provides the best results, however some camera apps contain features that I like (burst mode, etc.). I was wondering if apps such as Camera+ and Awesomize have an impact on the quality of photos?
The quality should be exactly the same. They both use the same API, so unless Apple applies some proprietary image algorithm on the picture, the source pixels are identical.
However, when those apps use the "burst" mode, then the quality of course will be decreased because they are in effect decreasing the resolution of the image for faster capture.
Any up-to-date camera app should have proper quality. However, I have noticed at least one camera app (I believe it was the two by Joby, Frame X Frame, and Gorillacam) that didn't seem to be optimized for the iPhone 4S's 8MP camera and instead used the quality level of the iPhone 4 - shooting 4MP photos. I've deleted both of those apps off so they may have changed something since then, but it has only been roughly a couple months since they were installed.
Again, they should have support, but not all do.