I have one 55gal with sand and the other with gravel. Personally I would go for sand. It looks nice and I have had no problems with my banana plants in either tank. Although they grow in almost anything!
If the people had sand eat up their filters it is, IMO
, most likely because their filter intake was right at the bottom. If you place it 2in above your substrate you should have minimal problems with that. And if you are going to be kicking up a lot of sand into the water by planting or rearranging/adding/subtracting elements to your tank or anything else, just turn the filter off until most of it settles back down.
If you find that your filter intake tube is too long and is not set up for adjustment, measure the desired length and cut off a little at the top. I have known many people to do just that.
Hope this was helpful and good luck with everything. Post pictures! I always love to see other's tanks. And let me know what you decide in the long run.