I'm not saying that. There are tradeoffs between the three types of filters. In a perfect world a cartridge filter will give you cleaner water but it is a bit more work and expense to maintain than sand. You have to decide for yourself how much time and money you want to invest in keeping your filter running. Be aware that some townships have outlawed all but cartrige filters because of the run off water from backwashing so some folks don't have a choice anymore. All three type of filters work well and all have been in use for a long time with proven track records. I have been very happy with cartridges and the views expressed above are only my opinions!

If you keep up with YOUR filter maintenance any filter that you choose should work fine. If you neglect it any filter will have problems.

As far as facts go I can tell you only this:
Sand will filter to about 60 microns
Cartridge will filter to about 20 microns
DE will filter to about 6 microns.

Filter care and maintenance is much more subjective. Some people find that cleaning a cartridge is a big chore. Some people find that maintaining a DE filter is too much work too. Sand is definately the winner when it comes to maintenance but then you have the backwash water to deal with. Same for DE as far as backwashing (which I don't think is a good idea.)

MY opinion is that a cartridge is a good comprimise among the three.
(ANY type of filter is going to be easier to keep clean on chlorine or bromine than on biguinide!)