I've had a sand filter in my old above ground pool, I currently have a cartridge filter for my in ground pool, and I maintain my dad's in ground pool, which has a DE filter. Of the 3 filter types, i think the DE filter probably filters the smallest particles and really makes the water sparkle. However, in my opinion, it is a pain the butt to maintain. It requires the most work. My sand filter....I loved it. Nothing to add, only needed to change out the sand once in 15 years, did a great job. But as with a DE filter, you need to backwash. My current filter, the cartridge style, takes care of my 41,000 gallon IGP. It requires absolutely no maintainence. After 10 seasons, I replaced the 4 cartridges, cost me about $250. So, for me, the lazy guy, the cartridge is the way to go, and it does filter really well.

Tom