Lots of good replies. Great!
My username is not an accident. I really have zero experience with this stuff, but chose cartridge because I didn't want to "Just add a little DE..." and then I would have to store it, then buy it, then "pump" it, then clean it... etc...
Sand filter was, for me, backwashing nightmare because of my small pool area. The less water spillage, the better. The less sand I see and touch, the better. and..... SAND.... It also didn't catch the smallest particles, so the middle one was cartridge.
What swayed me was the fact I could oversize the cartridge and possibly, being lazy, not clean the filter for a few months, or I don't know.... twice a season (in NJ). Who knows, I haven't had it running yet. I hope to get a low flow og my 2-speed pump and a large cart, with an extra cart that I already purchased and take my time cleaning it, or of course have someone else clean it. HA!!! jk.
I, too, have an swg and would rather keep the water in the pool.
Sure, I could be wrong. I'm a total newbie and had 2 or 3 weeks to decide all my equipment purchases. I'm sure I'll be fine with an 8000 gallon pool 200sf cart/w spare cart and 2 inch hard plumb pvc, 2-speed pump, with swg.
My carts cost $80 or so.