Hello; Allow me to open with a question. Which type of cichlid are you considering?
I have kept cichlids in tanks with sand and with gravel, it somewhat depends on the type. I generally use a quartz gravel substrate when possible (reference to your other thread) unless there is a particular reason to use sand. I find sand to have some issues in planted tanks, compacting when very deep and prone to lots of very fine suspended material in a tank if not pre-sifted. Unsifted sand will cloud a tank for a good while and can damage filter parts as this fine abrassive material cycles thru it. If using sand I dry sift it and discard the very fine material and then wash the stuff that will be used. When breeding kribensis I like to have a sand substrate as they like to dig a nest and the sand works well. I have also had them build a nest in gravel bottom tanks, so either has worked.
My recollection is that some cichlids, such as angels, do not pay any attention to the substrate at all while others will dig and move it around a lot. So, the type of cichlid you plan to keep will help determine which substrate to use.
Then there is always the matter of personal likes, I am one that likes a gravel substrate over sand as I usually have live rooted plants in my tanks. With some of the ciclids you will not be able to have rooted plants as they will up root them. Others that like sand will only use it.