I find sand much easier to maintain, but that just because of the way I do it.
I used a less bright more natural looking playsand so fish poop doesn't show up on it, and I have an army of hundreds of MTS churning it over, so any any food/poop/dead leaves get dragged into the sand. The MTS eat what they can, and the roots of my plants absorb the rest. I've never once cleaned my substrate since I set up my tank.
Look wise I prefer a mixture of sand and gravel at parts of the tank though, as I notice many rivers and streams have a mixture themselves.
I basically I just went to the local burn and tried to replicate what I saw in my tank.
If you get bright playsand, poop is going to show up really easy on it - great if your into regularly vacuuming the aquarium, but you cant use a gravel vac like you can on gravel.
Though I would still go for even bright sand over gravel, for fish like tetras, it doesn't make a difference, but for pretty much all bottom dwelling fish It makes a huge difference. My angelfish, ram and zebra danios even appreciate it too, sifting through it for food every now and then.
Much easier to grow plants in too IME.