I went the route of using Cerameco Detox blox for my 6 month old 50 cube with minimal aquascape. My nitrates wouldn't budge below 10ppm (salifert) before they went in. In about a month, my nitrates were undetectable, and still are. I have them setup in my sump as such:
You want to have them setup in a way that will allow them to get maximum flow through them. I havent had any issues with detritus buildup, they are in my fuge chamber of the sump. I have seen a lot of folks lay them on the bottom glass of the sump, but based on my experience, you want them elevated. I wouldn't necessarily say that they work any better than plain old live rock, but if you like to go minimal, they will definitely help.