The Concrete Limiter is my favorite PC module. I will without hesitation toss in on a track or buss because it does its job extremely well. Plus its a stingy CPU user. How CW was able to do that with a look ahead buffer and the total quality it offers is amazing to me.
As others have said its easy to use and it just works. I prefer it over all other limiters.
Some brought up a problem with the FX bin and PC that was true in X1 but not true in X2.
With X2 you can place any FX anywhere in the FX chain and place this in PC itself. You do not loose the ability to have the PC post or pre FX bin but now you gain the ability to place FX anywhere.