Im voting sand as well. IF you get the right kind and have the right kind of filter you shouldn't have to worry about sand clogging anything up. Generally it is easier to clean, looks better (IMO), and i think more fish prefer it. I will say however that disassembling a tank with it is an absolute chore. I just took one of my old tanks apart to use the materials in a small build i am doing in my dorm room. My parents where left to take care of it for a while and lets just say that the sand wasnt all that clean. When i took stuff out there was sand on EVERYTHING, and the cleaning of the sand itself took me a couple ours. Not a very clean job either.
My vote is still on the sand, as cleaning out your tank completely shouldnt that common of an event and if you take good care of your tank it wont get that messy anyway.