Very interesting post by Kevin McGinley about CAF here: CAF = Migration Utility? Use Caution!
It articulates better than I ever could reasons against using CAF particularly in a production environment.
Since the tool came out I’d been struggling to get my head around it, convinced I was missing something. I still don’t profess to understand it properly, but Kevin’s article reassures me that I shouldn’t be losing too much sleep over it, especially given that it’s unsupported and won’t work with 11g.