Hi Shawn,
I did the faux sand bed and really liked it for the first 2 months. After that, the entire bottom was covered with dark purple and dark green coraline algae. It looked awful to me and the tank constantly looked 'dirty' and dark. After another month or so of my wife saying "When are you going to clean the tank? It looks so dirty", I gave in and added 3/4" to 1" of white Fiji sand.
Instantly, the tank was brighter and much more pleasing to the eye and my wife thought I 'cleaned' the tank

I have 8200 gph going through this 240 and I have no problems with the sand blowing around in the water column. I even have 4 closed loop returns just an inch above the bottom of the tank (located in the back pane) and they do not cause any sand storms.
The sand has obviously been blown out from under the rocks but it has slightly piled up where the flow allows it and it does not move.
I've seen several bare bottom tanks around town and I honestly don't like the 'look' of them. The bottoms are inevitably covered in either dark purple or green coraline and most often, there are large piles of detritus spread throughout the tanks. I have yet to see a truly 'clean' looking bare bottom tank. The just look 'unfinished' and 'unnatural' to me now.
Of course there are many pics here on RC showing them, but I'd venture that the owners did a quick vacuum prior to the pics so it looked its best.
Its ultimately up to you of course. Personally, in a big tank like yours, I'd bet that sand would not be a problem regardless of your flow, especially up front where most of your viewing pleasure will be
