They even come in a variety of colors as well. Advancements in coatings techonogy has done some really neat things for firearms. My AR has a black teflon coats barrel. Makes cleaning carbon off the out side as easy as whiping it down with a rag. Bolt is chromed and cleans up just as easily. Gas system still can be a pain to clean out, but isn't really all that hard.
I'm the type that loves to tinker with stuff. No other gunsmith will ever touch this rifle unless I simply don't have the right machining equipement to do the job.