I agree, no debate. If carbon is used correctly it will do wonders for a reef tank. But, and I do mean BUT, it must be changed out frequently to do any good. It can only help the tank if it is used correctly.
I have been using carbon since the beginning of my reefing experience...only a short time compared to most, 2.5 yrs, but used it all the time in my FOWLR, and have never found it to do any harm. Maybe I am lucky, but if you change it out frequently......costly I know, but so is the hobby in general, you will not have any problems.
I have many leathers in my mixed reef and running it without carbon would have been a disaster from the on set.
There is a school of thought that carbon takes out the good stuff too, but my experience has been nothing but good. I will continue running it until proven wrong.....with my tank that is.
My two cents.....