I've used both the apps and each has its own merits going for it. Let me try and explain the difference so that it resolves atleast some of the doubts that people are having around here. Camera Plus is a camera app that has been around for quite some time actually (launched October according to their blog) and has AirSnap (remote control captures between 2 iOS devices), 3 Focus Modes and much more. The interface is quite aesthetic actually and i personally prefer it over several others.
Camera+, on the other hand, is the more popular of the two and has a lot going for it. And their release notes are pretty fun.
Hope that helps!