I have tried ZoomFX and Camera FV-5. Both have more controls but unfortunately the image quality was not as good as the stock app. I've stuck to using the stock app. I have wanted to try "Shot Control" app but I'm hesitant to try it considering these other two apps did not improve the camera.
The RMHD camera gets a bad rap. Though not a stellar camera I find it to be miles better than my Droid 2 Global camera. Make sure to tap the screen on the area you want the camera to focus on before you take the shot. Be aware of lighting conditions, this camera does not like low light.
Here is some objective data on camera quality of cell phones. Although this table does not have Maxx HD listed, the Razr Maxx is listed and I presume the Razr Maxx uses the same camera as the RMHD.
Photo Compare Tool - GSMArena.com