I just switched from gravel to sand in my tank. And If I can insert myself into this conv. here. SAND IS WAY CLEANER!!!! it doesn't always appear cleaner, BUT in actuality it is. Sand definitely puts more on your filters, because nothing gets stuck in the substrate like it does with gravel. But if you have a good trustworthy filter, and clean it regularly your tank will be cleaner than gravel. Gravel hides the gunk, sand doesn't, but just because gravel hides it so it APPEARS cleaner, does not mean that it IS cleaner. I have gravel and sand in my tanks, and I will say that it is way way way easier keeping the sand tanks clean, than the gravel, (both are pretty easy, but sand is def less work.) This is my opinion, like I said I just switched to sand from gravel, but I am absolutely loving it!!!! Everything gets sucked into the filter, and my substrate is completely clean.
Sand is a ***** to initially clean and get set up, to do it right takes hours, and even then your still going to have some cloudiness, but I think it is worth the extra initial work. It used to take me about 75 minutes to do a whole take down cleanout, water change, in my tank with gravel, now with sand it only takes like 45 min. I take everything out, I stir, I clean the glass and filters while I wait for everything to settle, and then you just hover over the sand with a vac, and EVERYTHING comes up.
I use Caribsea's African Cichlid Mix. Keeps the water clear, stable, and fish are happy, I have Lethrinops, and Aulonocara which pretty much HAVE to have sand. But I also like knowing that when my 12" JD freaks out, and gets scared by someone walking by, he is not going to mess his **** up crashing into the sand, He would get so many little nicks and cuts from gravel.