What filter to choose...cartridge or DE

[waterbear]

One thing I didn't see mentioned but I could have missed it make sure as part of the comparison you check the cost of replacement cartridges, sand or zeolite and D.E. so you know that information as well.
hth,
Jo

Sand is not that expensive and some say it never needs replacing. In fact, most of the people in this forum do, including Ben! There are some that will debate this point, however.
DE is dirt cheap (no pun intended...well, maybe a little pun) but you need to replace it all the time so it is a continuous expense.
Cartridges are the most expensive but with proper care they last about 5 years before they need replacing so you need to figure the cost over the time period.
Zeolite, IMHO, is not really any more efficient than sand and is more expensive. It 's main advantage is it's ammonia scavaging ability and it is being pushed as the "new miracle" for your pool! Not quite snake oil but some of the claims made for it's filtering ability come close!
There are some other filter mediums such as perlite and cellulose but they are not that commen. They are DE replacements but some can also be used in conjunction with sand and cartridge filters to improve the filtering ability much like DE can.