My current tank is the first one I've had setup with no substrate. It's only been running for about 3 months in my care, but the previous owner had it running this way for several years for a few years.
I decided to go the bare bottom route partly based on his successes with this method, but also to allow for virtually limitless flow options (no possibility of sand storms), to lessen the chances of scratching the viewing panes with my cleaning magnet (I have an acrylic tank), and out of paranoia of having a DSB crash on me sometime down the road.
The way that I aquascaped the tank helps make the tank look natural and keeps the focus away from the bottom of the tank. I have yet to have any visitors ask "where's the sand?"
For the first month, I noticed that nuisance algaes were starting to bloom, detritus would build up in certain areas, and I was getting really inconsistent skimming. After rearranging the flow patterns and performing a few 10% water changes, I've noticed that the tank looks really clean, nitrates stay below 10ppm, and my skimmer consistently pulls out a medium/dark green skimmate.