Samsung software.
High rez screen.
Mainly typical Samsung stupidity.
I have to agree Samsung does not build well. However concerning the tab s vs. IPad, sorry but the tab wins hands down. Higher resolution, faster processing, more and faster RAM, faster storage.
The trick is root, and custom recovery. Touch wiz is a serious performance killer. Find a room without it and this thing flies.
Regardless, apple needs to drop their price if they never intend to go higher than 2 cores and 1080p. It's bad enough they offer no customisation.