I would stay with sand, why do you want to switch? Both cartridge and DE are more work. I have a cartridge filter and if I ever get another filter I'll switch to sand. No DE for me, too much mess and too much work.
I agree. Love my SF for the reasons Danny mentions. You can always add DE to your SF for a little extra filtering. But if you are set on moving, nothing filters better than DE. I wouldn't consider a cart system on pool for love nor money.
I was all set to do the same thing a year ago until I got some wisdom from this site. I didnt realize water clarity was about chemical balance. As soon as I got my water balanced properly like this site recommends my pool cleared right up. Just add DE to your sand and you'll be amazed how great it works. So then you have the ease of a sand filter with the added benefit of DE. Cleaning those cartridges looks like a pita but i do like the idea of not flooding my yard with all the backwash water. My brother in law has one on his new pool so maybe I'll be convinced to switch one day depending how hard it is to clean and maintain. You'd definitely want a large cartridge so you dont have to clean that often is what I've read. Havent even thought of the replacement cost though...
Cartridge isn't bad until it comes time to clean them. I usually set aside a half day when I clean mine. This time it took over 5 hours due to these little pea sized shells from one of the trees in the back forest. I swear I 'cleaned' them 4 times before I got all those things out of there!!! (tried power washer on low and that didn't work very good)