S.2.
We've had 2 intex pools. You treat them like regular pools...chemicals needed every day, or every other (mostly chlorine). If you keep the chemical levels right then you should never have to scrub the sides. You'll need to skim on a daily basis, easy stuff. As long as you make sure kids step in a bin of water before going in the pool you might never have to vacuum. I think I only end up vacuuming once a season. Yes, the filter that comes with it works fine. Some people turn theirs on/off, but I let ours run 24/7. The instructions say to replace filter when it's gray/dirty but that can get expensive. I use 2 for the entire season....1-2x/wk I'll remove the filter and spray it with the hose to remove all the gray slime build-up then put it back in the filter. Half way through the summer I'll put in a new one. I also use straight bleach instead of pool chlorine. Soooo much cheaper. I know people with permanent above ground pools and they use bleach, too.
If you have any other questions you can PM me if you'd like. The pool is well worth it....not expensive and the kids will live in it!