R.J.
A LOT more than an inground pool.
Even if you go up 2-3 sizes on the filter... You'll need to clean the filter daily and clean the pool every couple days (there is no commercially available filter for above ground pools that does the job of an unground filter.
You'll ALSO need to be adjusting the chemicals several times a day any day the pool is in use, and typically 1-2 times a day it's not (the sun neutralizes the chlorine a LOT faster).
Temp also varies a lot more, but there's not a lot to be done about that.
Like any pool, it's as safe as the adults around make it. Kids drown in 2 inches of water. Eyes on, all the time.