I had an above ground pool and used a sand filter. I am in the process of putting in a gunite pool, and I'm getting the cartridge. Since I've had to remove the sand and replace it, I decided that the cartridge was easier to maintain. We had a spa that used the cartridges, and I loved only having to rinse them instead of digging sand out of a container, filling it back up and making sure the tubing stayed exactly correct and then having to put it all back together. Cartridge might be more expensive, but I think my time is worth it.

Just my two sense.