CFAR Detectors and Interference
The "best" detector is a highly subjective subject, and there is (in my opinion) not a definitive answer here. I work in radar processing and I've used everything that you've mentioned in one form or another.  All of these CFAR methods are tools, and all of them have good/bad applications.  For instance, asking what the "best" wrench is in the toolbox highly depends on what you're going to use that wrench for.  This is no different.  OS CFAR can help with non-stationary noise floors which are varying quite a bit from CUT (cell under test) to CUT, but sometimes CA-CFAR can work just fine and is much simpler to implement.  

In summary, they're all tools, and therefore no single CFAR detector is inherently "better" than any other one; it all depends on your system, the noise floor, the interference environment, the clutter environment, etc.