There are different steels I recommend for different use habits.
My diamond rod is meant mainly for line cooks that don't want to learn to sharpen with stones and just want a fast, no frills toothy edge on lower end knives. For instance, tons of people use Dexter Russels and they want to get an edge with a few swipes and not pay a lot of money to do it. For this person my rod works well.
Better knives with higher grade steels that cost more usually require better treatment than a 600 grit diamond rod. If you're using a rod for quick and light touch ups a smooth rod like the Idahone or the Mac Black ceramic rod are good choices. The F Dick smooth rod won't remove any metal at all and people that are descent knife sharpeners like this rod since it only aligns the edge and it doesn't grind at all.
So let me be more blunt (excuse the sharpening pun). Get the Idahone: http://www.chefknivestogo.com/sharpeningrod.html