In my opinion, a big problem with DSB's is that people load up their tank too quickly. It can take months for the infauna population to develop to a large-enough extent to properly process waste. In the mean time, people tend to add fish (and other waste producers) at a relatively rapid rate. Though the bacteria necessary for simple nitrogen processing can multiply fairly quickly, the animals that will deal with more complex organics take longer. So the unprocessed organics can accumulate (in the sandbed) in what has been called a "ticking time bomb".
In my opinion, sandbeds must be allowed to mature before fish (and most other anumals) are added. Even the modest clean-up crew additions can probably overwhelm a young sandbed.
So, if you want a tank looking nice in a short amount of time (months, not years), skip the sandbed, and have high-enough waterflow to keep detritus in suspension so that it can be removed from the main tank and collected in a filter sock, etc. in the sump.
That said, I consider the presence of a sandbed to be an important factor in my ability to keep thriving alveoporas. I believe it is the nutrients now coming out of my sandbed which keep them growing, as I do not feed them directly.